Headache

S4 E21: While investigating a grisly murder, Nick (David Giuntoli) and Hank (Russell Hornsby) get closer to uncovering the identity of the serial killer while Wu's (Reggie Lee) life is put in grave danger. Having turned down Monroe (Silas Weir Mitchell) and Rosalee's (Bree Turner) offer, Juliette (Bitsie Tulloch) solidifies a new alliance as she works to get her revenge. Elsewhere, Trubel (guest star Jacqueline Toboni) makes a surprising return to Portland.