As Nick delves into the trailer's weapons cabinet and his inner Grimm, the investigation of a dead construction worker leads him into a long standing conflict in the creature world. Sensing an unfamiliar threat, the suspect takes it upon himself to summon reapers to town to eliminate the Grimm once and for all. Meanwhile, Juliette insists that Nick invite Monroe over for dinner, making for quite the interesting evening.

After Juliette stumbles upon a brutal murder, Nick learns the suspected creature, and friend of Monroe, is suffering from a mysterious condition -- the inability to completely return to human form. This mysterious condition leads them to a therapist who's created an artificial drug to suppress the creature side, with horrifying side effects. Meanwhile, the investigation takes a surprising turn when Hank sees something he can't quite explain.