Beckman is raking Chuck over the coals. Not only did his rogue operation allow Frost and Volkoff to escape, he allowed his Intersect powers to be neutralized. A team of scientists will be working with him to try to restore his abilities. For the next month, Chuck is strapped to a chair and subjected to a battery of tests and treatments: exposure to strange and disturbing videos, being doused with water, being shocked, etc. None of it restores his ability to flash.
At Buy More, Jeff and Lester are growing suspicious: every new employee seems to be named Greta. Chuck, aware that Greta is a secret operative, tries to downplay any suspicion, but Jeff and Lester remain curious.
The CIA brings in one of its top men to help Chuck get his abilities back: a psy-ops expert named Jim Rye. As Chuck walks into Castle to find him, he's immediately waylaid by a pack of ninjas. Chuck tries to flash but can't - and is quickly battered by the attackers. Rye appears and calls off the assault. He explains to Chuck that his past therapies were ineffective and weak. Chuck needs to work with him using techniques that include pain, fear, and anxiety to break through his roadblock. Chuck's on board.
Rye assaults Chuck with a series of slaps and punches. Sarah catches this "therapy" in action and questions Rye's techniques. The unflappable Rye engages Sarah in some quick Kenpo karate to demonstrate how physical actions can stimulate dormant skills. Sarah holds her own, but she's still no fan of Rye. Still, Chuck is a willing student.
Back at their apartment, Sarah helps Chuck unwind with a massage. She explains that he'll be a spy in her eyes with or without the Intersect; Chuck's not so sure. Sarah wanders off to heat some massage oil. A black-clad attacker enters through the window, swords a-flying. It's Rye again, trying unsuccessfully to force a flash. Sarah and Chuck are appalled at the extent to which Rye will go to induce enough anxiety to free the Intersect from Chuck's subconscious.
Greta complains to Morgan: she's being stalked by two employees (Jeff and Lester) and warns that she has a way of dealing with people who annoy her. Morgan assures her that he'll keep an eye on them. But Jeff and Lester launch Operation Get-a-Greta, enlisting the help of fellow employees to track her every move and get to the bottom of who she really is.
Rye's latest plan is to go on a dangerous mission with Chuck to try to invoke the Intersect. Beckman agrees and informs Chuck and Rye that they're headed to Gstaad, Switzerland for a rare diamond auction known to be attended by terrorists and killers. Sarah's terrified of Chuck going on a mission without his Intersect abilities, but Beckman, Chuck, and Rye are convinced it's exactly what's needed. The mission is a go. A worried Sarah kisses Chuck goodbye. Don't be a hero, she begs him.
Chuck and Rye arrive at the auction and size up the diamond seller, Aldebert De Smet, aka "The Belgian." Their plan is to outbid the crowd for the diamond and bring it back to the U.S. Rye leaves Chuck by himself in the auction room, explaining it'll raise his fear factor and possibly induce his flashing ability. The Cane Volto diamond is put up for bid. Chuck is inexperienced at bidding, but quickly helps drive the price up, despite a Russian buyer who is threatening him with a gun. Rye watches approvingly. But there's still no flash. Chuck is outbid by the Russian. He and Rye make a plan to steal the diamond.
Morgan and Casey get wind of Operation Get-a-Greta. Morgan tells Casey they've got to thwart the investigation before her cover is blown. Casey tells Morgan he's on his own. Morgan catches Jeff and Lester and tells them to back down, but they refuse. Meanwhile Greta is at the end of her rope. She complains again to Morgan: they've put a webcam in her locker, bugged her price gun. Any more moves and she'll "neutralize the risk," she tells Morgan.
Chuck and Rye infiltrate the vault where the diamond is kept. But before they can access it, a security alarm trips and the room is pumped full of freezing gas. They have moments to live, but still Chuck can't flash. As their situation grows desperate, Rye enters a code on a nearby keypad, turning off the security measures. He knew the code all along, but again wanted to try to force Chuck to flash. They access the storage area for the diamond but discover there are actually multiple diamonds. They all appear to be fakes, i.e., glass stones embedded with some sort of microchip. They begin replacing the diamonds with their own fakes.
Chuck and Rye begin analyzing the fake diamonds; there's obviously some sort of encrypted data inside. As they work, Chuck's puzzled as to why he still can't flash, even under fear of death. Rye explains it's related to his relationship with Sarah. On a three-way videoconference, Beckman, Chuck and Rye, and Sarah and Casey argue over how to proceed. Beckman orders Chuck and Rye to capture The Belgian and recover the fake stones. Sarah's livid: Chuck's not a real spy without the Intersect. Despite Chuck's protests that he can handle it by himself, Beckman relents and dispatches Sarah to Switzerland to assist.
Lester and Jeff lure Greta to the Nerd Herd cage. They're determined to discover who she really is. As they try to play interrogators, Greta whips out her knife. It's looking quite hairy until Casey steps in and tells Greta to stand down. He's concocted a great cover story: Greta has been forging credit card slips and stealing head massagers. She's fired; Morgan escorts her off. Jeff and Lester have a few follow-up questions which Casey easily dismisses. The Buy More's CIA cover is still safe.
Back in Switzerland, The Belgian discovers the diamonds have been taken. He heads for the gondola that services the Swiss resort where they've been staying. Rye tells Chuck this is the perfect fear-of-death opportunity: the gondola offers no real escape. Meanwhile Sarah is en route, frantically calling Chuck, but he won't pick up. At Rye's urging, he's determined to capture The Belgian and get his mojo back at the same time - on his own.
The Belgian discovers that Chuck is in fact a valued CIA agent. As they ride the gondola, he orders Chuck to surrender. But he and Rye are having none of it; all hell breaks loose. As they engage in close-quarters combat, Chuck is thrown out the gondola door. As he hangs over the jagged peaks below he can only watch as Rye tries to take on The Belgian and his thugs. Despite the danger, there's still no flash.
Rye yells at Chuck. He must tell himself he doesn't need Sarah to be a spy; she's a rock that he must lift off of his true inner abilities. Chuck's not feeling it. He yells to Rye that he does love Sarah, that he needs her, and that he'd rather have her than have the Intersect. Rye is defiant: be a spy like me, he tells Chuck. But as he speaks, a bullet rips through his midsection. The Belgian has cut him down. Chuck watches in horror as Rye falls to the alps below. The Belgian pulls Chuck up into the gondola, a prisoner.
Back at Castle, Sarah frantically asks Beckman for permission to lead the team to find and free Chuck. But Beckman thinks she's too closely involved; she assigns Casey instead. Sarah's livid. She returns to their apartment and immediately begins packing for a rescue mission. Casey and Morgan show up and explain that wherever in the world Chuck is, they're going to help find him.
At an undisclosed facility, The Belgian addresses Chuck, who's restrained in a chair. Chuck is going to give up the Intersect, whether he is willing or not. The Belgian brandishes a syringe and an evil smile.