Rosalee and Monroe's big day arrives; a realization shakes Juliette and Nick's relationship to its core; Adalind's plan leads to a catastrophic event.

Black Claw makes a strategic move against Hank that shocks everyone and sends Nick on a war path. Hadrian's Wall ramps up their investigation as they seek out a mysterious man named Bonaparte. Meanwhile, Adalind and Capt. Renard must learn to deal with their new and very unpredictable reality with Diana.

The prophecy that was uncovered comes to pass when a dark force arrives in Portland with its eyes set on Diana. In an effort to protect her, Nick, along with Capt. Renard and Adalind, returns to the scene of his first investigation as a Grimm. Back at the Spice Shop, Monroe, Eve and Rosalee make a discovery that uncovers the origins of the mysterious stick. Meanwhile, Hank and Wu are called to a crime scene that is connected to the gang's greatest threat.

Monroe gets a call from a relative in Germany that will bring Nick closer to his ancestors. Things get complicated when the nefarious group Black Claw is also after the same artifacts. Elsewhere, Capt. Renard helps a mayoral candidate get an edge on his opponent. Meanwhile, Trubel confronts Eve about Nick and Adalind.

Nick faces off against his greatest foe yet as it seems no weapon can defeat him. At the Spice Shop, Monroe, Rosalee and Eve search for answers and stumble upon a rare potion that may help the fight. Elsewhere, Capt. Renard and Adalind try to keep Diana and baby Kelly safe as the threat has its eyes set on the children.

Monroe fights an impossible battle to convince his parents to embrace the life choices he’s made. Meanwhile, Nick turns to Juliette to help him figure out the Wesen aspect of his cop-killing scalper investigation. On the Royal Baby front, Captain Renard learns new information that forces him to contact Adalind in the interest of keeping her and the baby safe from Viktor.

Nick and his mom, Kelly Burkhardt, join forces to protect Adalind's baby. Meanwhile, Prince Viktor activates a deadly stateside asset to find Adalind and her child.

Nick and Monroe find a treasure in Germany that has been hidden for centuries. Back in Portland, Capt. Renard joins Hank and Wu to track down a deadly assassin who has thrown Portland into havoc. Little do they know that Eve is on a hunt of her own for the same man. Meanwhile, someone from Rosalee's past tracks her down.

As Nick delves deeper into his life as a Grimm, a trail of grotesque murders reignites the search for the elusive gold coins.

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

The Resistance's plan to keep Adalind safe gets kicked into high gear when an unexpected ally arrives to ensure she and the baby make it out of Europe safely. In Portland, as Monroe and Rosalee prepare for their upcoming wedding, Nick and Juliette are reminded of their failed proposal.

Nick and Hank learn the victims of the homicide they are investigating were from a special section of the Verrat; Renard grows suspicious of Adalind's behavior.

In order to stop the rise of Capt. Renard, Nick devises a plan that will take him out of his element. Adalind and Monroe do everything in their power to keep the plan on track. Meanwhile, Eve and Rosalee race against time to get the spell ready before it is too late.

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.

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.

A failed robbery leads Nick and Hank to powerful rare coins. Meanwhile, a suspect in the case may have information regarding the death of Nick's parents.

As Nick delves into the trailer's weapons cabinet and his inner Grimm, the investigation of a dead construction worker leads him into a long-standing conflict in the creature world.

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.

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

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.

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.

Nick and Hank investigate a cop killer who scalps his victims. Meanwhile, Juliette begins to communicate with Nick's mom via email and Adalind finds herself much closer to delivering her baby than she previously thought. Elsewhere, Monroe's parents decide to surprise him and Rosalee with an early arrival to Portland after learning some exciting news.

A horrible new predator creeps into Portland with its sight set on a young expectant couple who are close friends of Sgt. Wu. Nick and Hank must figure out how to deal with Wu as the investigation escalates. Meanwhile, Adalind prepares for a special delivery while her enemies are hot on her trail.

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 and Hank investigate a wave of coordinated Wesen gang vandalism that results in the death of a local business owner and the kidnapping of Monroe and Rosalee's friend. As they dig deeper, they learn that Portland wasn't the only city hit with a wave of violence. Meanwhile, Truble fills Nick and Adalind on what she has been up to. Elsewhere, Capt. Renard dips his toes into politics as he endorses a local candidate.