One Night Stand (Grimm)

Plot

The episode opens with a quote from Hans Christian Andersen's 'The Little Mermaid. Sarah's sister Elly, who loves Jake, spies on them and is sent away. Dan is dragged into the river by a creature; Jake tries to help but Dan drowns, while Elly saves Jake using a Wesen form. Nick and Hank learn Dan's body had claw marks.

Nick finds Elly at the scene, but she escapes into the sea. Renard learns from Sebastien that Adalind dealt with Frau Pech about the baby. Monroe and Rosalee, now living together, suggest the Wesen is a Naiad, a mermaid-like creature. Elly hides underwater as Sarah and Anna arrive; the police arrest them.

After they leave, Abel confronts neighbors Dominic and Jesse, the real killers, who decide to cut Elly. Abel confesses to Dan's murder to protect his daughters; Nick and Hank use the confession to get Sarah and Anna to reveal Dominic and Jesse as the killers, citing a tradition of caring for children. Jake finds Elly at his apartment; she takes him to a pool and shows her swimming abilities. Dominic and Jesse knock Jake out and kidnap Elly.

Reception

The episode was viewed by 5.81 million people, earning a 1.6/5 in the 18-49 rating demographics on the Nielsen ratings scale. It ranked third in its timeslot and fourth for the night in the 18-49 demographics, behind Hawaii Five-0, Shark Tank, and Undercover Boss. This represented a 19% increase in viewership from the previous episode, which had 4.88 million viewers and a 1.3/4 rating. With DVR factored in, the episode was watched by 8.49 million viewers with a 2.6 ratings share in the 18-49 demographics. The A.V. Club's Kevin McFarland gave the episode a 'B' grade, noting that while Grimm stumbles in broad strokes, it occasionally wins him over with attention to detail. Nick McHatton from TV Fanatic gave a 4.2 star rating out of 5, stating that the episode focused on a captivating tale with exciting serial elements.