Eric and the Baron try to smuggle a comatose Nick out of the country, but the Grimm wakes up and lashes out at his captor. Meanwhile, in Europe Stefania instructs Adalind in how to recover her Hexenbiest powers.
Eddie , Hank, Rosalee, and Juliette finally locate Nick and manage to subdue him and give him the antidote for the zombie drug. As they wait or him to recover, Renard risks incriminating himself and the others to cover Nick's tracks during his rampage. Meanwhile, in Europe Adalind continues her trials to regain her Hexenbiest powers.
Nick goes back on duty and is immediately assigned investigate a case where the victims have burst open due to bloat. Things take a turn for a worse when Nick and Hank learn that all of the victims were Blutbad. Meanwhile, Renard deals with the aftermath of his brother Eric's death.
When one boy is drowned and another narrowly escapes, Nick and Hank investigate reports of underwater creatures and find a family of aquatic Wesen. Meanwhile, Juliette reads a cryptic email sent to Nick and Renard learns what Adalind has been doing in Vienna.
A Wesen vigilante is responsible for the brutal slaughter of two robbers, and Nick and Hank discover that an old Spanish legend of "El Cucuy" may be involved. Meanwhile, Nick tells Juliette the truth about his mother and Renard takes an interest in Adalind's ultrasound.
Nick and Han investigate an apparent case of demonic possession when an exorcism goes bad and a monsignor turns up missing. They soon discover the incident is tied to a Wesen legend... one the Wesen Council wants destroyed for good. Meanwhile, Renard flies to Vienna to deal with the aftermath of his brother's death, and Adalind receives a mysterious summons.
While Nick and Hank chase a Wesen thief and killer through the sewers, in Europe Renard meets with the Resistance and Adalind makes the acquaintance of Eric's successor.
While Nick and Hank try to track down a horrendous beast dressed as Santa who is abducting naughty children, Eddie tries to share his spirit for the holidays with Rosalee. Meanwhile, in Europe Renard cements his ties to the Resistance.
When a waiter turns up dead, Nick and Hank discover that someone is stalking a Russian "healer," intent on revenge. Meanwhile, Juliette takes in a friend trapped in an abusive relationship, Hank's physical therapist turns down his invitation to dinner, and Renard makes contact with Adalind at last.
Nick and Hank investigate a gang-related homicide and discover that the only witness is the brother of Hank's physical therapist. Meanwhile, Nick tells Juliette that her friend Alicia is a Wesen, but Alicia refuses to discuss it with Juliette.
A deadly Wesen is stalking four men who committed a heinous crime during their time in Iraq, and Nick and Hank try to determine who the killer really is. Meanwhile, Rosalee gets an invitation to dinner from her estranged mother, and turns to Eddie for support.
While Nick and Hank track down a Wesen killer who takes the scalps of worthy opponents, Monroe worries about telling his parents about his engagement to Rosalee. Meanwhile, Juliette continues her correspondence with Nick's mother and Adalind has early birth contractions.
While Nick pursues the scalper killer, Monroe tries to deal with his prejudiced mother and father over his engagement to Rosalee. Meanwhile, Renard sends Meisner and Sebastien to help Adalind escape from Viktor before she gives birth to the baby.
Nick and Hank face a dilemma when a pregnant friend of Wu's is targeted by a Wesen that feeds on amniotic fluid. They have to decide what, if anything, to tell Wu about the Wesen community before he finds out for himself. Meanwhile, Meisner discovers that Adalind's newborn daughter has powerful abilities.
Wesen terrorists view the unearthing of a mummy as desecration and vow to steal it from the university where it's being kept. As Nick and Hank try to stop them, they keep a watchful eye on Wu, who is grappling with his sanity after seeing a Wesen. Meanwhile, Viktor finds the traitor in his organization, leading him to Adalind and Meisner.
Nick and Hank investigate the brutal deaths of two women and discover the trail leads to a carnival that has left a string of similar murders in its wake. When she learns that the carnival features Wesen transforming as part of its act, Rosalee sets out to help the performers. Meanwhile, Nick has second thoughts after he accepts Monroe's offer to be the best man at his friend's wedding.
Pachelbel -- Canon in D, Warren Zevon
-- Werewolves of London
The Resistance contacts an ally to get Adalind to safety: Kelly Burkhardt, Nick's mother. However, when the Verrat learn of their flight plan, Kelly has the pilot take them to Portland. Meanwhile, Nick tries to find a way to attend Monroe's wedding without giving away the fact that he's a Grimm.
Viktor and Ruspoli travel to Portland to force Renard to hand over Adalind's baby daughter, and Nick and Kelly try to come up with a plan that will ensure the baby's safety, free of the influence of either the Royals or the Resistance.
Nick and Hank investigate a dangerous female suspect leaving a trail of Wesen in her wake. Elsewhere, Adalind takes measures into her own hands, even if that means forging a dangerous alliance.
Nick (David Giuntoli) does his best to educate Trubel on how best to handle the world she is learning about for the first time, and decides it best to bring her on a ride along with Hank. They find themselves investigating the homicide of a young woman that strikes a chord for Trubel. Meanwhile, Adalind makes a discovery that she hopes will lead her to regain something she has lost.