The accidental discovery of a microchip launches Claudia from her heaviness into action mode. Inserting the chip into a flash drive, the team discovers a video from Jinks telling them that Sykes is planning a trip to Hong Kong, the site of Warehouse 7 as well as of the Regent Sanctum.
Sykes's trail leads Pete and Myka under the streets of Hong Kong to a deeply buried lair where Sykes has his computer hacker, Tyler, strapped into a chair with an axe above it and Wells, controlled by Sykes via Cecil B. DeMille's riding crop, pointing a gun at the young man's head. It seems the key to unlocking the Regent Sanctum lies in winning a game of chess played against a bewitched chess set. But should the human player make the wrong move, his head will be split open by the axe above.
Wells pleads with Sykes to release Tyler and give up his crusade, but Sykes does not relent and Tyler loses his life. Upon discovering the two agents, Sykes turns his weaponry (namely, Wells) on them and forces Myka to have a go at the deadly game. With the stakes raised, Wells is able to remember words of wisdom from her mentor, the man who invented the chess lock: "Change the rules." Wells instructs Myka to make a move with her pawn that defies the rules. With a shudder, the axe disappears and the wall next to them transforms into a portal leading to Warehouse 13. Sykes uses Pete as his new puppet and the two men pass through the portal, which Sykes closes before Wells and Myka can follow.
Artie and Jane are trapped inside by means of Jane's shackle, which raised an impenetrable field when it felt the threat posed by Sykes's henchman, Marcus, who aimed an artifact cannon at the Warehouse. Since Marcus is still alive and Sykes is entering the Warehouse, the threat is active, meaning no one is getting out anytime soon. Sykes turns son against mother and forces Jane to retrieve the Collodi Bracelet. The villain dons the manacle and his eyes deepen to an inky black. He stands, his full faculty restored, and forces Pete to turn the gun on himself. Jane is in agony and begs that her life be taken, instead, but Sykes is pitiless.
But Wells and Myka have reopened the portal and manage to get a lucky Tesla shot in before an artifact ensnares them in its ropy tangles. Sykes quickly recovers, but the crop is lost. He continues his pursuit of Jane, who flees through the reopened portal and as Sykes runs after her, Pete closes the portal, trapping Sykes in solid rock.
Pete calls his mother via Farnsworth to make sure she's okay, then returns to Artie, Myka and Wells, surprising the latter with a heartfelt hug. They then contact the inn, where Claudia tells them that Marcus is dead thanks to the combined efforts of herself and Mrs. Frederick. An artifact - a metronome - had been keeping the man alive and when Claudia stopped its rhythm, Marcus's heart stopped with it. Against Mrs. Frederick's wishes, Claudia intends to use this same metronome to bring back Jinks.
If the threats to the Warehouse have been eliminated, why hasn't the barrier disappeared? Some threat must still be present in the Warehouse. Artie pieces together clues from Sykes's words and discovers an atomic bomb in the dead man's wheelchair. As he, Myka and Pete attempt to disarm it, Wells quietly rigs some wires and extends the Warehouse's protective field around her three compatriots. She wasn't able to include herself in the bubble - it had to be created from outside - but she is grateful to know that her friends, and the rest of the world, will be safe from the atomic blast.
As flames rip through the aisles, Myka sends a forlorn look to her lost-and-found friend, and hundreds of years of artifacts are destroyed. The blast clears and Pete voices his sense of defeat after such a long battle.
Pete didn't count on Artie, who reveals a mysterious pocket watch, and utters a sentence that hints that thoug the battle may seem lost, it is not yet over.