After their face-off with Kimura (guest star Brian Tee), Nick (David Giuntoli) finds himself trying to come to grips with the return of his mother, Kelly Burkhardt (guest star Mary Elizabeth Mastrantonio). A trail of brutal murders unveils a foreign conspiracy to hunt down Nick, leading to several revelations about his past. Meanwhile, Juliette ("Bitsie Tulloch") still lies in her mysteriously-induced coma as Rosalee (Bree Turner) and Monroe (Silas Weir Mitchell) work tirelessly to bring her out of it safely. Elsewhere, Hank (Russell Hornsby) struggles with the shocking truths he’s recently seen and Captain Renard (Sasha Roiz) deals with unexpected family issues when his estranged brother (guest star James Frain) comes back into his life. Reggie Lee also stars.

As Nick (David Giuntoli) and his mother (guest star Mary Elizabeth Mastrantonio) continue to battle the Mauvais Dentes (guest star Mike Dopud), Monroe (Silas Weir Mitchell) and Rosalee (Bree Turner) fight against the clock to save Juliette (Bitsie Tulloch). More details are revealed about the source of Juliette’s illness, resulting in an epic showdown. Back at the precinct, Hank (Russell Hornsby) senses that something is amiss when Nick lands in hot water with the FBI. Meanwhile, Captain Renard (Sasha Roiz) continues to reveal himself as he deals with his estranged brother (guest star James Frain). Reggie Lee also stars.

As Hank continues to seek help to cope with the inexplicable siting he had, an old friend, Jarold Kempfer, needs his help when his daughter goes missing. Nick’s expertise as a Grimm comes in to play as he investigates the disturbing motives linked to the disappearance.

During the investigation of an accident site, Nick discovers a disease that is quickly spreading; Monroe and Rosalee come across an infected creature; Captain Renard gets a tip about a dangerous fugitive.

When a local Reverend reports that his church has been robbed, Nick quickly learns that it’s a Wesen church, and enlists Monroe to check for any suspicious activity regarding the shepherd’s flock. Meanwhile, Nick and Juliette continue to figure out the rules of their relationship as a dangerous opponent lurks in the shadows with his sites on Nick.

Angelina comes to town with bad news; Nick asks Hank for help keeping Monroe safe; Captain Renard receives a visit from a past acquaintance.

An investigation into a grisly murder leads Hank and Nick to a seemingly unstable man who is on the run with his daughter; Monroe realizes that filling in for Rosalee will be harder than he thought. Meanwhile, Juliette continues trying to remember more about Nick while Adalind calls Renard and demands to know who killed her mother.

Nick and Hank are called to the scene of a murdered high school academic decathlete and learn just how competitive some extracurricular activities can be, and the extremes some coaches and parents will go to give students the best chance for success. In other police matters, Captain Renard deals with an unwanted infatuation while we learn an old accomplice of his has been spending time with his family in Europe. Elsewhere, Monroe continues to manage the spice shop and gets a visit from an unlikely customer.

Despite the enthusiastic anticipation of the city’s residents for Halloween, a series of horrifying child abductions make their way to Portland, quickly spoiling the holiday spirit. Nick and Hank join forces with Valentina Espinosa, a mysterious detective from Albuquerque. The more Nick digs into the case, the more he realizes the pattern of the kidnapping matches those in the famed Hispanic legend "La Llorona," a story with its roots intertwined with his own family’s history. Meanwhile, Monroe celebrates the holiday in fine style as he teaches the neighborhood bullies a lesson.

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.

Hank starts reflecting on an arrest he made earlier in his career regarding a man who committed murder claiming “self-defense against monsters.” With the man’s death sentence rapidly approaching and the knowledge he’s recently gathered from Nick, Hank begins to wonder if there was more truth to the man’s seemingly absurd story then he once thought. Back at the spice shop, Monroe finds himself involved in a situation he never saw coming.

Adalind returns to wreak havoc as she avenges her mother's death; Captain Renard's obsession escalates; Monroe receives a surprise visit.

Nick deals with the consequences of learning the truth about Juliette and Capt. Renard; Nick must investigate his own crime; Wu responds to a shooting at Nick's house.

Nick, Monroe and Hank discover that members of a Wesen community have been responsible for a series of bank robberies; Juliette questions her mental state.

When a mysterious case of sudden blindness causes a woman's death, Nick and Hank come across a disturbing Wesen that feeds off its victim's tears. Meanwhile, Adalind contemplates the significance of her new situation, while Juliette continues to work with Rosalee in an effort to fix her memory.

When a gruesome homicide brings an office party to a screeching halt, Nick and Hank find themselves battling a Wesen on a completely new platform - online. Meanwhile, Juliette’s mysterious hallucinations finally start to take shape, giving them a whole new meaning.

Rosalee asks Hank, Nick and Monroe for help when a defense attorney tries to use Wesen wiles to overturn a murder case; memories rush back to Juliette when she returns to the trailer.

Nick finds himself fighting a wildly different sort of nature freak in a desperate attempt to keep a volcano from burying Portland in lava. Meanwhile a pregnant Adalind meets a powerful new ally in Europe. Meanwhile, Juliette seeks out help after becoming overwhelmed by the latest side effect of her recovery – multiple memories of Nick showing up everywhere.

Mysterious cow mutilations and reports of glowing creatures put Nick on a case that forces him to question the existence of aliens within the Wesen world. He also meets a strange UFO expert who seems to know more than he’s letting on. Meanwhile, Nick digs further into the key, and Juliette’s romantic memories of Nick start coming back in a big way.

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.

Nick and Hank discover a new kind of strange when they investigate suspects being found dead - for the second time. In Europe, Adalind finds herself in the middle of a feud between Frau Pech and Stefania while working over the details of her pending transaction. Meanwhile, determined to remember every last detail to get things started once more, Juliette insists Monroe share with her Nick’s darkest secret - the world of Grimms and Wesen.

Season finale: