Secret Service agents Lattimer and Bering are "rewarded" with a transfer to the top-secret Warehouse 13. They meet Artie Nielsen, the caretaker of the mysterious warehouse, who tells them about their new job. The agents are responsible for the collection of every supernatural and unexplained item that the U.S. Government has ever collected. For their first assignment, they are sent to Iowa to investigate a possible artifact belonging to a college student who went berserk and assaulted his girlfriend while chanting an Italian incantation.
Bank robbers use a musical weapon to go on a crime spree. Pete and Myka chase down the thieves while Artie investigates a hacker who tried to enter the warehouse's computers.
Pete and Myka travel to a small town where the residents are slowly going insane due to the influence of an artifact. Meanwhile, the mystery hacker gets closer and closer to the warehouse's location.
A psychiatric patient, Claudia Donovan, kidnaps Artie and insists that he help rescue her brother... who is caught in an interdimensional void.
A mysterious thief uses an artifact to steal a Native American sculpture, and Pete and Myka must determine what the thief's ultimate goal is... and how to stop them.
An explosion in a St. Louis police station reveals the inactive person of a Warehouse agent... and unleashes a potent artifact upon the world.
The agents are sent to Washington to recover a samurai sword that can render its wielder invisible. However, when the sword is stolen, they realize that a rival artifact collector is involved... and he has ties to Artie's past.
While doing inventory in the warehouse, Myka is unknowingly trapped in a mirror belonging to Lewis Carroll... and replaced by a mirror image psychopath who goes with Pete to Las Vegas to recover an artifact two conmen are using to win at the casinos.
When four prisoners commit suicide at a maximum-security prison in as many weeks, Artie sends Pete and Myka to investigate. Meanwhile, a frustrated Claudia decides to use an artifact coat to change a light bulb, and chaos ensues.
Arnie is summoned before his mysterious superiors, the Regents, who question whether he's following the rules. Meanwhile, Claudia accidentally sets off a catastrophe in Warehouse 13 and works with Pete and Myka to stop it before the system explodes.
While hunting down MacPherson, Myka receives word that her father is dying. She discover that he's the victim of an artifact, one that someone intentionally sent to him.
MacPherson manages to steal artifacts from the warehouse and put them up for bid. However, his scheme is part of a much greater plan, one that may potentially end in disaster for everyone.