
Portland detective Nick Burkhardt, descended from a long line of warriors known as Grimms, defends his city from magical creatures known as Wesen, which are part human and part animal. Fighting alongside his partner, Hank, colleague Sergeant Wu and friends Monroe and Rosalee, Nick faces off against internal and external forces, including his police captain, Sean Renard.

Nick tries to suppress a volcano's threat to Portland, Ore.; Adalind meets a new ally in Europe; many simultaneous memories of Nick overwhelm Juliette.

Cow mutilations and reports of glowing creatures lead Nick to question the existence of aliens in the Wesen world; Juliette has romantic memories of Nick.

A muselike Wesen possesses the ability to influence people she approaches; Juliette tries to clear the air with Nick; Rosalee visits Aunt Marie's trailer.

Hank and Nick encounter zombies; Adalind is caught in a feud between Stefania and Frau Pech; Juliette asks Monroe to reveal Nick's darkest secret.