After their face-off with Kimura, Nick finds himself trying to come to grips with the return of his mother, Kelly Burkhardt. A trail of brutal murders unveils a foreign conspiracy to hunt down Nick, leading to several revelations about his past. Meanwhile, Juliette still lies in her mysteriously-induced coma as Rosalee and Monroe work tirelessly to bring her out of it safely. Elsewhere, Hank struggles with the shocking truths he’s recently seen and Captain Renard deals with unexpected family issues when his estranged brother comes back into his life.

As Nick and his mother continue to battle the Mauvais Dentes, Monroe and Rosalee (Bree Turner) fight against the clock to save Juliette. More details are revealed about the source of Juliette’s illness, resulting in an epic showdown. Back at the precinct, Hank senses that something is amiss when Nick lands in hot water with the FBI. Meanwhile, Captain Renard continues to reveal himself as he deals with his estranged brother.

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.

Hank and Nick investigate when a high school competition turns deadly; Capt. Renard is faced with an unwanted infatuation.

Nick realizes a series of child abductions that he is investigating bear a striking resemblance to the Hispanic legend of ``La Llorona.''

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.

After Nick learns about Juliette and Captain Renard, he must deal with the consequences. Things get even more complicated when Nick is called to investigate his own crime. Meanwhile, the search for the key intensifies as Captain Renard finds Nick’s trailer and makes a surprising alliance. With Rosalee’s help, Monroe informs Nick that they might be able to stop what’s going on with Renard and Juliette before it goes too far. Elsewhere, Wu responds to a bizarre shooting at Nick and Juliette’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.

While trying to work out the ramifications of his new alliance with Renard, Nick investigates a murder where the victim was blinded with parasites sprayed into her eyes. Meanwhile, Juliette's hallucinations become clearer, and Adalind asks for help with her pregnancy.

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.

While on jury duty, Rosalee tasks Nick, Hank and Monroe to help stop a defense attorney from using his particular “Wesen wiles” to overturn what should be an open-and-shut murder case. Back at the precinct, Captain Renard brings Nick and Hank in on his own recent dealings with the Verrat, to keep them on their toes. Meanwhile, a return to the trailer brings a flurry of memories of Nick rushing back to Juliette.

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.

Just when things look like they’re back to normal with Juliette, Nick is called to investigate a flurry of rage-fueled assaults happening all over Portland. He goes to Monroe and Rosalee for help battling Portland’s newest wave of "undead." As if that weren’t enough, Captain Renard informs Nick that his brother Eric is in town on family business. Meanwhile, Stefania and Frau Pech methodically use their alliances with Adalind to battle one another.