Season 4 kicks off with the Warehouse Team still reeling from the shocking events of the climactic season three finale – the loss of Agent Steve Jinks, Mrs. Frederic, H.G. Wells, and the destruction of the Warehouse itself. Their only hope lies in racing to the other side of the Earth to hunt down an obscure artifact, which may or may not even exist – and if it does exist, what consequences will they face for using it?

Pete and Myka investigate a mysterious case where mobs of angry people are hallucinating

All hands are on deck to prevent a small town from being wiped off the map when a box of artifacts is accidently unleashed.

Pete and Claudia reunite with Hugo to track down a deadly artifact at his nephew's prep school; Myka and Steve investigate an artifact that is killing a musician in New Orleans.

Pete and Myka investigate a hockey player who is miraculously recovering from his injuries; Claudia is invited to a mysterious lunch with Mrs. Frederic; Artie and Steve has discovered that someone is stealing artifacts from the warehouse.

The team discovers someone has stolen Lewis Carroll's mirror from the warehouse.

Pete and Myka cross paths with an inquisitive drug company exec; a pill is making people taller; Artie, Steve and Claudia track Brother Adrian to his hideout.

Pete and Myka investigate a case of people rusting away; Steve and Claudia visit Steve's hometown to end his dependence on the Metronome; Artie tells the truth about Brother Adrian and his use of the Astrolabe.

Brother Adrian sends deadly artifacts to the agents loved ones; Mrs. Frederic and Steve discover the truth about Artie and Adrian.

The Warehouse’s battle against an unspeakable power that has steadily consumed Artie Nielsen comes to a devastating conclusion.

Pete and Myka race to stop a global plague before it kills half the world's population.

While Pete and Claudia travel to Oregon to look for an artifact used to kill enemies of the environmental movement, Artie deals with the repercussions of Leena's death.

Pete and Myka get sucked into a 1940s detective noir novel in search of an artifact.

Pete and Myka head to Vegas to investigate murders that are tied to the world of high magic. Meanwhile, Claudia and Jinks search for an artifact used to rig horse races, while Artie meets the new B&B owner, Abigal Cho.