After investigating a strange cluster of female deaths and disappearances, Nick sends Monroe undercover to get a whiff of a hypnotic suspect. In the meantime, a stranger shows up looking to avenge the death of his friend at the hands of a Grimm, but he'll have to get past Captain Renard.

Nick and Hank's investigation of a dead high school teacher leads them to the school's outcast, Roddy. Nick realizes that there's more to Roddy than meets the eye, and enlists Monroe's help to get through to the troubled teenager before he exacts revenge on the students who wronged him. Meanwhile, Nick learns that his presence is beginning to affect the creature world.

After some of Portland's homeless youth go missing, Nick discovers a black market supplying the Grimm world with human organs. As the investigation continues, Nick and Juliette befriend a pair of homeless siblings, Hanson and Gracie, whose friends have gone missing.

Nick and Hank search for a dangerous heartbreaker who leaves behind a gruesome corpse and apparently her finger. Nick and Juliette's safety is threatened when the creature world begins to discover his identity.

A failed robbery leads Nick and Hank to powerful rare coins. Meanwhile, a suspect in the case may have information regarding the death of Nick's parents.

During the investigation of an accident site, Nick discovers a disease that is quickly spreading; Monroe and Rosalee come across an infected creature; Captain Renard gets a tip about a dangerous fugitive.

While trying to work out the ramifications of his new alliance with Renard, Nick investigates a murder where the victim was blinded with parasites sprayed into her eyes. Meanwhile, Juliette's hallucinations become clearer, and Adalind asks for help with her pregnancy.

Mysterious cow mutilations and reports of glowing creatures put Nick on a case that forces him to question the existence of aliens within the Wesen world. He also meets a strange UFO expert who seems to know more than he’s letting on. Meanwhile, Nick digs further into the key, and Juliette’s romantic memories of Nick start coming back in a big way.

Nick and Hank discover a new kind of strange when they investigate suspects being found dead - for the second time. In Europe, Adalind finds herself in the middle of a feud between Frau Pech and Stefania while working over the details of her pending transaction. Meanwhile, determined to remember every last detail to get things started once more, Juliette insists Monroe share with her Nick’s darkest secret - the world of Grimms and Wesen.

As a deadly crime spree begins to surface, a century-old urban legend takes shape in Portland's sewers and becomes Nick's latest case. In Europe, Adalind meets Prince Viktor, who’s come to bring those responsible for his cousin Eric’s demise to justice. Meanwhile, Captain Renard responds to the recent attempt on his life.