Chuck Versus the Truth

The episode opens to find Mason Whitney, a government specialist, bound to a chair undergoing interrogation. He is injected with a toxic derivative of pentothal by Reardon Payne (Kevin Weisman), a former gymnast-turned mercenary and is told to retrieve the nuclear codes he has hidden in exchange for the antidote. At the Buy More a woman named Lou (Rachel Bilson), who owns a deli in the mall, comes in experiencing phone problems which Chuck fixes. Afterwards, Morgan teases Chuck for flirting with Lou. Later, Chuck, Sarah, Ellie and Awesome are on a double-date, when Awesome remarks that Chuck and Sarah have been taking things very slowly. On their way out of the restaurant, Whitney stumbles into the group and collapses. Ellie immediately comes to his aid and calls in an ambulance. Before losing consciousness, Whitney slips something into the pocket of Ellie's sweater. Chuck flashes on Whitney as he is loaded into the back of the ambulance with Ellie.

Sarah waits with Chuck at home until Ellie returns. She tells them the doctors were unable to save Whitney and she believes he was poisoned, then decides to go to bed. Sarah takes Awesome's comments about their relationship seriously, and announces to Chuck that for the purposes of their cover, it's time they make love. The next morning Lou returns to bring Chuck a sandwich to thank him for fixing her phone. Sarah arrives, and Lou leaves in disgust at the thought Chuck would cheat on his girlfriend, despite Chuck's protests. Sarah, Chuck and Casey examine Whitney's corpse and discover a bug behind his ear. Meanwhile, Payne, disguised as a police officer, goes to Ellie's house and exposes her to his poisoned pentathol derivative, while also planting a bug on her. That night Sarah arrives at Chuck's home. Although nothing is actually going to happen and everything is for appearances, she and Chuck get into a fight. She realizes that Chuck is interested in Lou, but because of their cover, pursuing a real relationship outside their cover would be extremely difficult. Ellie, under the effects of pentathol, gets into a fight with Awesome as well, and barges into Chuck's room. They all take Ellie out to the living room while Casey, listening in over his bugs, picks up cross-talk interfering with his signal and comes to investigate. Ellie passes out, and they discover that she has been bugged just like Whitney.

Ellie is rushed to the hospital in a coma while the team tries to decide how to proceed. Against Sarah and Casey's objections, Chuck sets up Payne by using the bug planted on Ellie to suggest they found Whitney's codes and planted them on her. Sarah disguises herself as Ellie by donning a wig, and when their target arrives, she and Casey ambush him. He threatens to expose them to the poison as well if they don't give him what he wants, but offers the antidote for Ellie if they turn over the codes. Meanwhile, Chuck is watching over Ellie, and while she's unconscious he confesses to her about his secret life. Awesome arrives with her sweater, and Chuck finds the codes. He races to deliver them to Casey and Sarah, but accidentally runs into Payne, releasing the poison and infecting all four of them. Payne escapes and grabs the codes, but drops both the tracker he used to monitor his bug and the antidote. There is only enough for one of them, and Chuck elects to give it to Ellie instead of himself, despite Sarah's insistence and Casey's threats.

Chuck finds Payne's tracker and realizes they can use it to find his location. They track him down and confront him in his apartment and he offers to share the antidote with them, but Chuck calls his bluff, knowing he can't lie under the effects of the truth serum. Payne tries to fight his way out but Sarah shoots him in the knee. Under the influence of the drug he helps them locate the real antidote. Before Chuck and Sarah drink it, he asks her if they could ever have a real relationship but Sarah declines. Later at the Wienerlicious, Chuck tells her that they need to break up their fake relationship, then joins Lou at her deli. When Casey calls Sarah to ask if she compromised herself while under the influence of the truth serum, she responds in the negative but also reveals that she had been trained to resist its effects all along. This is the first verbal mention (if indirect) that she has real feelings for Chuck.

Morgan is assigned by Big Mike to help Harry Tang's wife pick out a birthday gift for him. Morgan meets her in secret by the Video Wall, where Poppy Tang explains she wants the biggest TV they have in stock. Morgan goes to draw up the paperwork, when Poppy gives him a big hug in gratitude for his assistance. Unknown to either, Jeff and Lester are making a recording of the event. The two later show the video to Harry, who thinks his wife is having an affair with Morgan.

Harry intends to confront them in the Home Video room and breaks in, only to discover Casey, Chuck and Sarah being debriefed by Beckman and Graham. Casey plays on Harry's ego by telling him they've been watching him for a while and intend to recruit him. They arrange for Harry to move to Hawaii. Later, when Morgan reports to Big Mike, Mike tells him to change the shipping address, since Harry has moved. Big Mike also admits that while he couldn't stand Harry, he and Poppy were having an affair.

• Chuck flashes on Mason Whitney. He incorrectly identifies him as a threat.
• When Chuck finds Whitney's codes in Ellie's sweater pocket he has another flash to identify them.
• Chuck flashes on Payne's fingerprint, which Payne had accidentally put on the tracker.