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 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.
Monroe explains to Nick about the feral Coyotl prison gang-like, even tattooed kind's pack code when they find on old friend of Hank is actually one who fled his pack years ago and now finds his daughter kidnapped. The trail leads to their Texas relatives, the Kempfers, who stop at nothing but ignore the other side has a Grimm. Nick shows angelic patience when Juliette's memory returns about everything except their love.
Park ranger Ryan Gilko is the first of several Wesen, affected by a contagious disease, who suddenly commit violent attacks on people. The team felt relaxed now Hank is being included in the secret, so Monroe takes Rosalee on a picnic. Alas, the plague spreads and even affects her, so it's up to Monroe to make the remedy they researched together while Nick holds her feral state in check. Captain Renard meanwhile learns that another terrifying European fugitive has arrived in Portland.
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 sights on Nick.
Nick is delighted when Juliette, who still can't remember him, invites home for a home dinner to get acquainted all over. But he's called away urgently by Monroe, who has a feral visitor: a ruthless killer, yet also a friend of his, who only pretended to take a contract for his death to warn him after 'accidentally' killing the initial hit man. Nick, who wants her for at least two earlier murders, grudgingly cooperates, even has to allow her pretending to be his partner. To get to the royal presumed to have hired a killer, Monroe must fake his death with a potentially...
Even Nick is puzzled by the case of two murdered teenage favorite candidates to the high-school general knowledge quiz qualifying for the state competition. Wesen in the story belong to several species, one extremely rare. Captain Sean Renard wins a community prize and turns to Monroe for a medicinal cure for his sexual obsession with Adalind Schade. Surviving competitor Pierce Higgins is actually an unwitting Wesen-halfbreed. In Vienna, his brother, prince Eric, confide into his latest conquest.
After sleeping on it Nick decides it would be best for Monroe to take Juliette to the trailer. However, the trailer triggers more memories of Nick than Juliette may be able to handle leading her to seek the help of Pilar for insights into her current condition. Meanwhile Monroe fears Rosalee, who is serving jury duty, maybe under the influence of a toad dropping Ziegevolk who is jury tampering to win his case. Nick, Hank, Bud, Monroe and Rosalee hatch a plan to stop this Ziefevolk once and for all.