When a brutal vigilante homicide is made public, it sends Portland’s Wesen community into a frenzy. As Nick investigates further, he discovers a pattern similar to that of a particularly brutal line of past Grimms. Is there another Grimm in town, or is Nick dealing with a sadistic copycat? Meanwhile, Captain Renard takes it upon himself to offer Juliette comfort in handling her ongoing dilemma with Nick.

Nick discovers a muse-like Wesen with the ability to influence those she gets close to – some with positive results, others with terrifying ones. Nick must find a way to get close without losing himself in the process. Juliette arranges a dinner date with Nick in the hopes of clearing the air, but their plans go awry as the case intensifies. Meanwhile, Rosalee takes her first visit to Aunt Marie’s trailer.

When Nick and Hank 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 starts unpacking her things at Monroe’s, and Captain Renard makes a startling realization about the possible identities of the Royal Baby’s parents.

When Nick brings Trubel on a ride along with Hank, they end up investigating the murder of a young woman; Adalind is hopeful after making a discovery.

A rabbi raises a golem to protect his nephew, but he can't control it. Elizabeth successfully recreates Adalind's spell, but it still requires a key ingredient.

When an arson case looks to have Wesen origins, Nick find himself reluctantly having to ask an old foe for help. Elsewhere, Viktor teaches Adalind the effectiveness of well-played diplomacy. Meanwhile, Juliette finds herself in a confrontation sooner than expected.

A string of homicides have the press asking Captain Renard if a Jack the Ripper copycat has arrived in Portland. While dealing with the investigation, Nick, Hank, Monroe and Wu deal with a situation they never expected. Meanwhile, Adalind and Rosalee must work together on a last ditch attempt to fix Juliette's condition. Elsewhere, Juliette decides to help her new ally even if it means hurting those around her.

Rosalee disappears after some orphans decide she is the mother figure they always wanted and an encounter with a former colleague prompts Adalind to consider going back to work.

A barbaric Wesen ritual is brought to the present and Nick, Hank and Wu are already five steps behind the serial killer. To aid in the investigation, Monroe goes undercover. Meanwhile, Hadrian's Wall's war against Black Claw intensifies as Eve uses her unique skills to interrogate a suspect.

Nick leans on Monroe and Rosalee as he worries that he may lose everything as he continues to battle Black Claw. Renard ramps up his campaign as election time nears. Elsewhere, Adalind is faced with a very difficult decision in order to protect her children. Meanwhile, Hank's relationship with Zuri takes an unexpected turn and Wu tries to gain control of his new reality.

Rosalee surprises Monroe with a getaway for his birthday and invites most of the gang to join them. Things take a shocking turn when a hotel employee targets Nick in an effort to avenge his father. Meanwhile, Eve gets a visit from a dark force that she has seen before. Elsewhere, Capt. Renard spends the weekend with Diana when a former ally decides to get even.