An alarm in a sector of the Sanctuary has Magnus and her team scrambling to secure all of the abnormals - a toxin is somewhere in the air, and the crew needs to get all of their sensitive guests to safety. Will and Kate drive a van to a secure location, but before long, they're ambushed. It seems, however, that their attackers were only interested in one creature - the collective of microorganisms that formed a suit and turned a tubby nerd into a self-styled superhero named The Adjuster. Will is knocked out and Kate, trying to save the abnormal, is wounded, but in the melee, the case of the suit is cracked, and the organism latches on to Kate just as it had to Walter, the original Adjuster.
The Sanctuary force soon learns who masterminded the theft: A weapons developer named Virgil St. Pierre. Kate, who has been abducted by Virgil's goons, is strapped into a machine designed to detach the suit from its wearer, but something goes wrong, and Kate's brain activity is jolted. The machine has impaired her judgment while the suit has given her superpowers. By the time Magnus catches up to her, Kate is on a gleeful rampage of revenge. The new challenge is how to get the suit off Kate before it impairs her brain permanently - a feat made more harrowing by the fact that Virgil, who mutated microorganisms in order to make them a suit in the first place, has sold the suit to the Russian mob, and needs to get it back to them before he literally loses his head.
Magnus, having called in Walter, lures Kate to a secure location and attempts to get the suit to transfer itself to Walter. After the success of his comic book and movie, however, Walter is a different person - the suit doesn't want him. When Virgil arrives, Kate speeds off, and the Sanctuary team go back to the drawing board. Walter is crushed, but determined to help. He overhears Virgil's true intentions - to kill the suit if he can't get it back alive - and decides that he'll do whatever's necessary to right his wrongs. After a chase in which Kate knocks down every Sanctuary staffer save Magnus, Walter arrives on the scene. Magnus is able to get through to the altered Kate, and Walter, thoroughly humbled, convinces the suit to leave Kate and attach itself to him. And not a moment too soon: Virgil and his henchmen arrive with guns at the ready, but Walter is swift and knocks them all to the ground. Magnus tells Virgil that she's had a chat with his contact in the Russian mob, and that his message was clear: If Virgil stays out of Magnus's way, he'll live.
Magnus brings Kate back to the Sanctuary for treatment, and Kate is glad to be safe and home. Walter returns to the set of his movie with a new integrity, and sees to it that the truth of his story is restored.