22 people arrive at the castle. Claudia reveals to the audience that she will select a fourth "Secret Traitor" alongside the three regular Traitors, unknown to viewers, players, and the other Traitors. Each night, the Secret Traitor will create a shortlist from which the regular Traitors must choose a murder victim; however, the Secret Traitor could not put their own name forward.

Rachel, Stephen and Hugo are chosen as the Traitors and after learning of the Secret Traitor, decide to try to uncover and banish that person as fast as possible.

• Shield Mission: In rowboats, three teams of players search for coffins floating on a lake with gold in them, transport them to shore and place them in any of the graves named after the players to add £1,000 to the prize fund. The players whose named graves remained empty are shielded from murder.

The group wins £10,000. Ross, Netty, Maz, Judy, Rachel, Adam, Reece, Faraaz, James and Fiona end up with coffins in their named graves.

Netty and Ross announce that they know each other, but had not been in contact for over ten years, whilst Roxy reveals to the audience that Judy is her mother.

The Secret Traitor shortlists Netty, Maz and James for Murder.

The Traitors murder Netty. At breakfast, players interrogate Ross for his connection to Netty.

• Shield Mission: The players push three throne-bearing chariots to the castle from the hills above, stopping three times to collect gold or shield tokens. Players seated on thrones at the castle are protected from murder, but anyone who picks up a shield token can force someone currently on a throne to swap places with them.

The group wins £8,750. Jade, Amanda and Faraaz remain on the chariots at the end of the mission and are awarded shields.

Suspicion falls on Ross due to Netty's murder, and Judy for her attitude changing and for admitting that she turned at the word "Traitors" during Claudia's speech after the Traitors were initially chosen. At the Round table, Judy is targeted for being a big personality and is banished. She is revealed as Faithful. Ben tells Jessie, Ellie, James, Fiona, and Stephen he now suspects Ross.

In the turret, the Traitors discuss theories about the identity of the Secret Traitor, focusing on Ellie and Fiona as likely candidates.

The Secret Traitor shortlists Maz, Ben and Reece for murder.

The Traitors murder Ben. Hugo loudly denounces the decision at breakfast, drawing attention. Ross surmises that Ben's parting words might have put a target on him.

• Shield Mission: In teams, the players recreate paintings from written descriptions for others to match to the real paintings in a room full of them.

The group wins £5,000. One of the paintings also features a shield necklace, and the first player to find that painting is granted a Shield. Adam finds it and is protected.

At the Round table, Harriet interrogates Hugo for his unusual behaviour and formally accuses him. Others speak about Reece's urgency in looking for a Shield as being suspicious. Ultimately the players, including Stephen, vote to banish Hugo, who subsequently reveals that he is indeed a Traitor.

The remaining Traitors are secretly told there would be no murder that night, and are given a task asking them to mark nine players on the family tree with red paint to nominate them for murder. Rachel successfully does so. The Traitors' prize for this is that the Secret Traitor's identity is revealed to them that night, and from that point on they will become a regular Traitor.

Fiona is revealed as the Secret Traitor. Nobody is murdered, and Claudia announces that the round table will take place before the challenge instead of after. The group discovers the red paint on the family tree, and Stephen regrets placing himself on the shortlist.

At the round table, James accuses Reece of being a Traitor due to his interrogation of James at the prior round table. Ross is again brought under scrutiny due to his friendship with Netty, and Ben's final words. Ross is voted out over Reece by one vote, and announces that he was a faithful. Ellie reveals to the audience that she is Ross's girlfriend.

• Mission: Those shortlisted for murder are placed in cages, whilst those not in danger pick a player and save them by finding and stacking ten skulls. The first five successful players have their partners released.

The group wins £10,000 and frees Amanda, Faraaz, Jack, Jade, and James, leaving Sam, Reece, Maz, and Stephen in cages. Fiona appears to purposefully stall so not to free Reece, whilst Sam is not chosen by any of the uncaged players and so is automatically selected as a candidate for murder. Fiona and Rachel are forced to meet in the turret without Stephen, and debate which one to murder.

The players theorise that Stephen will be the one murdered. Maz is murdered face-to-face by the Traitors.

• Mission: The players are each allocated a shield. They have to find ten spears in the woods and set them alight; however, with each burned spear they must choose a player whose shield will also be burned, making that player eligible for the next murder.

The group wins £9,000. Amanda tells Rachel that she is a former detective.

At the round table, Jessie accuses Stephen of being a Traitor as he was in the library for Ben's final words. Amanda is placed under suspicion for accusing Reece of being a Traitor and stating that she would vote for Jade, despite previously stating that she was voting for Sam. James and Jack continue to accuse Reece. The votes are tied between Reece and Amanda, and then tied a second time, taking it to a random draw. The pair choose a chest each; Amanda selects the empty chest and is therefore banished, subsequently revealing herself to be a Faithful.

After the round table, Rachel informs everyone that Amanda had told her in confidence that she was a police detective. Fiona privately accuses her of lying, and then publicly accuses Rachel of being a Traitor. Rachel then accuses Fiona of being a Traitor. Rachel, Fiona and Stephen meet in the turret to decide who to murder.

Rachel and Fiona continue to argue in the turret. The Traitors choose to murder Reece, shocking the faithfuls.

• Mission: The players split into three teams and make their way through the woods answering questions about the other players. The team with the most correct answers wins a prize. In the event of a tie, the team with the fastest time wins.

Faraaz, Rachel, Harriet, Roxy, and Matthew win. In a subsequent elimination game, Rachel, Harriet, and Matthew are given the opportunity to speak with the Traitors that evening and ask two questions each.

At the round table, Fiona and Rachel continue to accuse each other. Jade comes under suspicion due to Amanda's accusations before banishment. Sam continues to be accused of being a Traitor. Stephen and Jessie bring up that Fiona was in the room for Ben's final words. Ultimately, Fiona is banished and revealed as a Traitor, with her voting for Sam and both Stephen and Rachel voting for her.

Stephen and Rachel meet up in a confession-type room for their individual meetings with Matthew and Harriet. Matthew arrives first and asks who they planned to murder next.

Rachel and Stephen answered Jessie for being too obviously a faithful. Matthew agrees with this assessment. For his second question, he requests that they murder Jessie, and then recruit him as a Traitor and asks if they had a deal. The episode ends with the Traitors' written reply to him as yet unopened.

The Traitors agree to the deal with Matthew. Harriet then enters and reveals her true job as an author of psychological thrillers and a former barrister. She first asks who they plan to recruit.

The Traitors reply Harriet, Sam and Jessie. Harriet accused them of lying and then directly calls Rachel out by name as being in the confessional, shocking both Stephen and Rachel. She asked if the traitors will protect Rachel.

Stephen and Rachel reply "No. Take her."

At breakfast, Matthew refuses to reveal his questions and Harriet directly calls out Rachel.

• Shield Mission: Place eight cherub statues around the Faithful Fountain. In the Fountain itself, players find cherub coins with the location of a statue. The coins then free the statue from the plinth. Players can decide whether to take a shield which will forfeit any money the statue was worth. All statues must be found or neither the money nor the shields count.

The players divide into teams and run to get the statues. On finishing the mission, seven shields are taken and they bank £3,000.

Stephen, Rachel, Faraaz, Jessie, Jade and Jack all get shields and James also secretly takes one without his team realising – though later admitted it to his team.

Since the initial plan was for Jessie's shield to cover James, Adam, Sam and Harriet, Sam is very annoyed at James since seven shields meant the odds of being murdered were very high for those without. He publicly reveals to several players, including Stephen, that he is not the one with the shield.

At the round table, Harriet accuses Rachel but other players are suspicious that her evidence is not substantial. Rachel also defends herself by revealing that she had undergone training prior to the start of the game with a former FBI agent, who had instructed her in body language and the study of micro expressions. Harriet also accuses Roxy and Matthew of being traitors and tells everyone to vote her out to prove she is a Faithful to give her argument legitimacy.

Harriet is voted out and reveals herself as a Faithful.

In the turret, Stephen and Rachel debate recruitment or murder. They do not wish to murder someone in either of their teams and are unsure who didn't have a shield in the remaining team. In the end, they decide to take a gamble and murder.

At breakfast, it is revealed that the traitors have successfully murdered Adam - Rachel and Stephen correctly deduced that: it would be too risky to try and murder Sam because he might have been bluffing about not having a shield; Jessie was the most likely to have taken one shield for herself with the agreement of her team, being the most liked; and James was more likely than Adam to have taken a shield without his team's knowledge. James taking a shield and not telling his team is viewed as potentially traitorous behaviour.

Suspicion falls on Sam after he claims that everyone knew he and Adam did not have the shields based on their reactions. However most players had only known Sam didn't.

• Shield Mission: Set in Claudia's Cabin, players must correctly identify names cryptically given to them that match a headstone in the graveyard outside. Players can also choose to take the shield headstone instead of banking money.

After working out the first name, Sam immediately goes out first, declaring that he is going to get the shield; this immediately causes suspicion among the remaining players. The players successfully bank £4,000.

At the round table, several players are accused: Sam for both previous suspicions and how only someone in Adam's team could have known that he didn't have a shield; James for taking a shield sneakily and also being in Adam's team; Stephen is accused by Jessie who had come back around to the cage theory; Jade for Amanda's suspicions and having a link to Adam as he had voted for her previously; Matthew for being accused by Harriet and also having been voted for by Adam.

Sam is eventually banished with six votes and reveals that he was a Faithful.

After the round table, Jessie pushes her Stephen theory while Stephen and Jade suggest that Jessie could be a traitor trying to waste round tables by checking off people from the cage mission. Rachel also puts suspicion on Faraaz.

In the turret, Stephen and Rachel agree that they are never going to recruit Matthew but worry that alerting him to this would cause him to reveal any hidden suspicions he might have about them. They debate the risks of murdering Jessie. They also consider Faraaz since neither of them want to have too many "definite faithfuls" in the final.

The episode ends with them deciding to murder one of the three.

The Traitors decide to murder Jessie, with Stephen hoping to spin it as him being framed. At breakfast, Rachel says she had an idea of a traitor.

• Mission: Players hide inside giant boxes and have to answer questions about themselves that match the answers of the traitors. However, the traitors have not given their answers yet. Rachel and Stephen have to climb out of the boxes and quietly answer the questions before getting back in and voting with the group.

They bank £3,250.

At the Round Table: Jade comes under scrutiny for Amanda's accusations, how many murdered players have voted for her, and, during that day's challenge, answering her own name for who didn’t deserve to be in the final; James for hiding his shield; Ellie for her answers in the mission being largely aligned with the traitors' and Rachel implies she had been hanging around her to get information after her announcement that morning.

Ellie is banished with four votes. She reveals that she was a faithful and that Ross is her boyfriend.

Claudia announces that there will be no murder that night and instead hosts a dinner party. The eight players all talk about what they would do with the money if they win.

Towards the end of dinner, Claudia arrives and shows them a dagger. Instead of a murder, the traitors will decide who to give the dagger to as it will entitle them to an extra vote at the next round table.

Stephen and Rachel meet up in the wine cellar to decide who will receive the dagger.

James is given the dagger. This casts suspicion on Matthew, with James believing he and Roxy are traitors attempting to divert suspicion. Roxy meanwhile believes James is a traitor who gave the power to himself. Jade continues to be accused. Matthew tells several others that he believes the traitors will vote for him.

• Shield Mission: The players spin on a carousel and then find gold bags hidden within toys. However, with every round, chairs are removed and the last person seated wins a shield.

Jack wins the shield. On the car ride back, Faraaz discloses to Matthew and Roxy his suspicions about Rachel and Stephen, which he was keeping hidden to avoid being murdered.

At the round table, Matthew accuses Jade as he believes she is too defensive. James accuses Matthew of attempting to cause confusion. Stephen calls out how Matthew had said traitors would vote for him as being suspicious. Roxy is placed under suspicion for being seen at the family tree before the shortlist by Jade, and Faraaz for being too quiet. Roxy and Jade both accuse James. In the subsequent confusion that left everyone torn on who to vote for, Matthew is banished and subsequently revealed as faithful. James is left in absolute shock that his suspicions had been so wrong, and believes that he has sealed his own fate by drawing so much attention onto himself.

After the round table, James is placed under further suspicion for his emotional response to the banishment. Faraaz informs everyone of his belief that Rachel is a traitor before accusing her directly. His theory is based on how Fiona’s outburst could have been traitor vs traitor.

At the turret, Stephen and Rachel discuss whether to murder Roxy or Faraaz. Rachel tells Stephen that she may have to accuse him, causing him to doubt their alliance.

Rachel and Stephen choose to murder Roxy. Jack and James are newly suspicious of Rachel because of Faraaz's prior comments, with Stephen agreeing. Rachel continues to accuse James. Faraaz asserts his suspicions about Rachel, Jade, and Stephen.

• Mission: The players hike up to the Fyrish Monument whilst collecting gold and doing challenges to pay respects at the graves of the contestants. If enough gold is collected, the traitors are prevented from murdering.

The players successfully collect £10,000 and prevent the murder. Both Jack and Faraaz agree that they are going to accuse Rachel. Stephen tells the faithfuls he thinks either James or Rachel is a traitor. The players worry that the round table will be the last time the banished roles would be revealed.

At the round table, Jack opens by accusing Rachel due to Fiona and Harriet's prior comments. James, Faraaz and Jade all lay out their suspicions of Rachel as well. Stephen attempts to divert attention by accusing James due to his erraticism at the previous round table. Jack and James are further placed under suspicion due to always voting for the same person. Stephen then accuses Jade as she voted for James, despite being suspicious of Matthew. Faraaz brings the conversation back to accusing Rachel. Rachel then accuses Stephen as he survived the cage murder and he retaliates by accusing her of copying Harriet to seem less suspicious.

The votes are tied, with Stephen voting for James instead of Rachel. James and Rachel both plead their case before a second vote takes place. To many players' astonishment, both Jade and Jack change their votes, leaving the tie in place and the banishment to be decided by the chests of chance.

Rachel wins the game of chance and James is banished. He reveals that he is a faithful, devastating Jack in particular.

Stephen admitted he isn't sure if he can win now that Rachel has survived. Rachel attempts to convince Faraaz that she isn't a traitor by claiming she believes it is Jade. In the turret, Rachel and Stephen reaffirm their alliance but separately doubt its security in their confessionals. Jade suspects Faraaz and Rachel, whilst Jack entirely suspects Rachel. Rachel and Stephen plan to banish Jade at the round table.

• Final Mission: The players have 45 minutes to drive speed boats to get gold off of pontoons before their flares run out and then reach the top of Loch Orrin dam. They collect £9,000. The players are then told they can add another £10,000 to the prize pot by running face-first down the side of the dam to reach a helicopter in five minutes.

The players successfully add £19,000 to the prize pot. Going into the final, the total is £95,750.

Jack tells Jade that he feels that Rachel had tried to guilt trip them during her final plea. Jade points out to Jack that Faraaz has never voted for either of the successfully banished traitors and that seemingly backing down from Rachel after the round table was suspicious. Faraaz tries to convince Jack that they should go to endgame together by banishing Jade first, then Rachel, and Stephen. Jade tells Stephen all of her suspicions about Rachel.

At the round table: Faraaz accuses Jade based on Amanda's suspicions; Jack accuses Rachel of guilt tripping while Stephen points out that Rachel's demeanour after the previous round table was different. Jade is banished at the round table with three votes.

Because Stephen voted for Jade, to whom he had been very close, Jack wonders if he is a traitor. Rachel and Stephen confirm their decision to vote for Faraaz next. Rachel and Faraaz discuss voting for Stephen, and Jack and Stephen discuss voting between Rachel and Faraaz. Stephen privately weighs up the pros and cons of trying to eliminate Rachel.

At the endgame, everyone chooses to banish again. Faraaz votes for Stephen, Jack votes for Rachel, and Stephen and Rachel vote for Faraaz. Faraaz is banished, meaning the Traitors have won the game.

All three remaining players choose to banish again. Rachel votes for Jack. Jack votes for Rachel. Stephen votes for Jack, choosing to stay loyal to Rachel over winning alone. Jack is banished.

Rachel and Stephen become the first traitor duo to win The Traitors, each taking away £47,875.