Monroe treats Rosalee to a lavish dinner and afterwards, shows her an antique cuckoo clock. When the clock strikes midnight, the cuckoo pops out holding a ring, and Monroe proposes to Rosalee on the spot. Rosalee accepts the proposal, but she adds that she finally wants to meet Monroe's family. Monroe is not thrilled about his new fiancée's request.
Across town, a car races down a Portland street in the dead of night. A highway patrolman clocks the vehicle traveling at over 100 miles per hour and gives chase. The car stops in the woods, and as the pursuing officer approaches, he discovers that the vehicle is empty. Suddenly, a vicious Wildesheer Wesen strikes from behind, killing the officer and scalping his victim.
The next morning, Nick and Hank arrive at the scene of the gruesome murder. Police don't have a great deal of information on the suspect, but Nick and Hank know they're dealing with a seriously demented perpetrator. Later, Captain Renard lays it out on the table: they're tracking a serial killer who targets police officers. The detectives will have to proceed with extreme caution.
In Austria, Adalind meets with the leaders of The Royals, who question her about her connections to Eric's assassination. They know that Renard was in Vienna recently and that he made contact with Adalind. After she leaves, the leaders decide they'll need to learn which Renard brother is the true father of Adalind's unborn child.
That night, the Wildesheer Wesen attacks a war veteran in a dark alley. The veteran puts up a good fight, but the Wesen eventually overpowers him. The next morning, Nick and Hank find the body of the veteran, brutally beaten and scalped. They quickly connect the dots between the two murders: both victims were uniformed authority figures who were scalped after they were killed. The suspect's car is spotted across town and Nick and Hank head to the scene.
The suspect steals a truck and gets away just before the detectives arrive. In the abandoned hotel room, they discover hair follicles from nearly 30 possible victims. Nick and Hank head to the trailer to search for a possible Wesen link to the murder spree. The entry for the Wildesheer strikes a familiar note: the Wildesheer search for warriors and scalp their enemies upon victory. Hank points out that Nick should be at the top of the list for a Wesen who targets warriors.
Monroe's parents stop by to have dinner and meet Rosalee. The meeting does not go as Monroe had planned. His father is disappointed that Rosalee is a different species of Wesen, and the encounter erupts into an argument. Rosalee leaves in an angry rush, encouraging Monroe to work this out with his parents. Monroe is irate. At the most inopportune time imaginable, Nick arrives. As soon as Monroe's parents see the Grimm, they morph into their Wesen forms and attack!
Nick and Hank hunt a vicious Wesen murderer on a killing rampage who only chooses "worthy" opponents.