After months of hopeful expectation at the post office, Myka's personal effects are finally delivered - but Pete's are still missing. Myka doesn't have long to enjoy her homey treasures before Artie sends her and Pete off to Detroit to investigate a vigilante who can bend steel and hurl people through walls. A local officer takes them to Loretta's Coffee Shop, to see if they can glean some information from the neighborhood watch, but they are soon pulled away by another crime, where they discover something truly bizarre: A crime-fighting superhero, whom Pete identifies as the Iron Shadow.
The only information Pete gathers from the warehouse is that Artie is more cranky than usual. Things are tense between Leena and Claudia after MacPherson used Leena as his pawn, but what really has Artie bothered is that he keeps seeing images of MacPherson. Finally the girls get him to confess, and the three decide that on Rasputin's Rosary is responsible for the haunting. They give it a good cleansing, but the time working together has been too much, and Leena and Claudia have a nasty fight.
Myka and Pete question Loretta and her friend Sheldon, but when they prove to be a dead end, the pair head to the comic book shop for some research. Pete, who has all the Iron Shadow issues but one, utters the Iron Shadow's catchphrase, which Myka heard Sheldon say earlier. They decide to question Sheldon further, and head to his house. He soon confesses, only to turn into his alter ego, demand they leave Detroit, and fly away. Myka deduces that he's altering his density, but still has no idea how. The team believes that Sheldon is using Jack Kirby's Belt, and as Myka and Pete follow Sheldon to the coffee shop, Claudia heads to Detroit with a counter weapon. Sheldon's anger causes gravity waves that accidentally injure Loretta. Panicking, Sheldon flees.
Artie, meanwhile, is still not rid of MacPherson's ghost, and at Leena's urging, he finally discovers the true cause of his former partner's presence: The death they shared by grace of the Phoenix.
Myka prepares to don Claudia's invention - an energy-absorbing suit and redirecting gloves - and the team, with Loretta, head towards Sheldon's hideout, the defunct auto factory. Myka makes contact with the contrite Sheldon and absorbs his energy, and Claudia and Pete rush in to neutralize the belt. As they do, Sheldon's density again builds to maximum, threatening to pancake the entire city. Sheldon yells to them that it's his superhero's trunks causing the density manipulation. Heroically, Myka steps in to siphon and redirect his energy once again. She reaches him just in time, and they neutralize the trunks. Given Sheldon's mild-mannered demeanor and regret at his actions, they decide to let him go, to live a normal life with Loretta. Humbled by this display of forgiveness, Claudia decides she can finally forgive Leena. They all head home, where Artie has made peace with MacPherson and purged the warehouse of his ghost. And Myka has a housewarming surprise waiting for Pete: a giant TV, and, more importantly, issue #146 of The Iron Shadow - the only issue missing from his collection.
Warehouse 13 is back for its final season, premiering Monday April 14 at 9/8c.
On a rainy day at the Warehouse, Pete accidentally triggers an artifact that transforms the team into two-dimensional diorama versions of themselves, and returns the Warehouse to its original, unstable design.
Saul Rubinek's talks about his family's way of celebrating the holidays and a spoiler on the series final season!