One Night Stand
When Nick (David Giuntoli) and Hank (Russell Hornsby) investigate a drowning death with mysterious marks on the victim's ankles, they happen upon a group of water-bound Wesen with a deadly postcoital cuddle. Meanwhile, Rosalee (Bree Turner) starts unpacking her things at Monroe's (Silas Weir Mitchell), and Captain Renard (Sasha Roiz) makes a startling realization about the possible identities of the Royal Baby's parents.