Recovering from the horrible explosion set by McPherson, Myka and Pete search for Artie, and are amazed to find him in one piece thanks to the Phoenix amulet. But his use of that artifact means that someone else must die, and soon the three learn that Mrs. Frederic's driver was the unfortunate, and Mrs. Frederic was badly injured as a result.
As Myka and Pete search for clues, Artie delivers the news that Claudia has been traced to Switzerland. He goes to find her, ordering Myka and Pete to stay put. But they soon discover that another debronzing has taken place - someone set H.G. Wells on the loose - and so they follow the lead to London. Once there, at the Wells residence, they encounter a further surprise: Wells is a woman, and handy with a gun. She uses her intelligence and wiles to trick them into delivering her quarry - an invention called the Imperceptor Vest - and makes her getaway.
Artie, with the reclaimed Claudia, is hot on the trail of McPherson in Switzerland, but upon reaching her brother Joshua's research lab, Artie discovers he is moments too late - McPherson diverts the guards' attention and makes his getaway with stolen research material. Artie, Myka and Pete piece together that, since Claudia is now cleared of suspicion, the leak in their team must be Leena.
But Mrs. Frederic is one step ahead of them. Arriving at the B&B, she asks some keen questions, and, receiving troubling answers, strangles Leena. But there was a method to her madness: Leena awakes, and Mrs. Frederic explains that she had to do that in order to release Leena from a mind control tool - called a Pearl of Wisdom - planted by McPherson.
By this time, Wells and McPherson have united at the warehouse, with the Imperceptor Vest now powered by the antimatter McPherson stole from CERN. They head for the Escher Vault - the lockdown containing the personal effects of the bronzed captives - where Wells heads inside. Artie and the team figure out what Wells and McPherson are up to, and head carefully back to the Warehouse, knowing there will be many traps in their path. Artie and Claudia carefully pick their way through, while Myka and Pete just sail through on a zip line. Using the thimble, Myka tricks McPherson as Pete lays handcuffs on him, and Claudia and Artie come running along. McPherson begs to exchange his freedom for that of Wells, who is still in the vault, but as he does, Wells overhears, cuts off the beads that were saving his life, and speeds away. As McPherson dies in Artie's arms, he apologizes for his sins, and expires.
The team conducts a post-mortem, and to make up for the bumpy road, Artie delivers a Farnsworth to Claudia. But the tender moment doesn't last for long - it's back to work. Mrs. Frederic discovers that Wells took a mysterious locket, ring and compact, making her recovery even more pressing.