Portland detective Nick Burkhardt learns he is a Grimm, descended from a long line of warriors charged with protecting humanity from magical creatures known as Wesen, who are part human and part animal.

After a couple break into a house, Nick and Hank meet a mysterious family, while elsewhere Monroe tries to safeguard Aunt Marie.

A man puts the song `YMCA' on his speakers in a tram, which makes the other passengers dance inside. When everyone leaves the streetcar, the driver discovers a woman dead in the streetcar.

When a young woman is found dead wearing nothing more than a nightgown, Nick is called to look into the suspicious circumstances, suspecting that this might be a murder. As the investigation goes on and he uncovers a string of female disappearances, Nick finds that he may be after a creature with hypnotic abilities that has a penchant for beautiful women. Elsewhere a reaper arrives in town looking to avenge the death of his friend.

Hank and Nick are called to a high school to look into the gruesome death of a teacher. As the investigation continues all the evidence points to a troubled musical prodigy named Roddy. While Nick delves deeper into the mystery he recruits Monroe to try and speak with Roddy, to divert him off a path that would see him destroying his future for vengeance. Elsewhere Nick learns that his presence is affecting the creature world.

A man is practicing with a Shake Weight but he accidentally throws it out of the window. When he goes to retrieve it, his house explodes. When Nick and Hank question him, Nick sees him do something very unusual.