Nick is searching high and low in Aunt Marie's trailer. Before she died, Marie entrusted Nick with a key and told him to guard it with his life. Nick still has no idea what this key is for, yet believes whatever it unlocks must be in Marie's trailer. Eventually, Nick stares at the key long enough to notice the carvings on the outside and decides to make an impression of the design on a piece of paper. Sooner than he can finish, Juliette calls to remind Nick they're late for their double date with Hank and his new girlfriend. Nick wonders who could be making Hank so giddy lately and is completely floored at the restaurant when his partner introduces Adalind, the vicious Hexenbiest Nick's previously encountered.
Captain Renard is brought by gunpoint to meet his cousin from Germany in a deserted parking lot. The cousin explains the family is concerned things aren't going as planned. Either surrender the key now or the family will take the Grimm and find it themselves. The cousin is uninterested in Renard's excuses, so Renard turns the tables and shoots both his cousin and his cousin's henchman. Apparently, Renard is equally uninterested in the family. Later, Renard visits Adalind's mom, Catherine. Promising Catherine's debt will be paid once Adalind helps Renard acquire the key, Catherine asks what will happen after Renard has it. "Those who helped will be rewarded. Those who didn't will be forgotten."
Nick can't disguise his animosity toward Adalind during dinner. Continually throwing around veiled accusations toward her, both Hank and Juliette are puzzled by his actions. Nick confronts Adalind when they've stepped away from the table and warns her to stay away from Hank. Adalind taunts Nick by asking him to try and stop her. Moments later Nick is actually excited to receive a request to investigate a double homicide. Certainly beats following dining etiquette with a Hexenbiest.
Unbeknownst to Nick and Hank, they are investigating the deaths of the two men Captain Renard killed. Nick tries to put together the pieces of the parking lot crime, which has been made to appear the two men shot each other, but the evidence isn't adding up. Hank finds a cell phone under the car that they hope will identify whom else the men have been talking to. At the scene, Nick notices Sgt. Wu eat an entire stick of Chap Stick. Wu is still suffering from the side effects of eating the love potion-laced cookies meant for Hank.
Back at the station, Wu eats the change from the vending machine after purchasing a soda. Captain Renard is concerned to learn Hank found one of the victim's cell phones. Is there a clue he forgot to remove? Wu becomes delusional, saying random things about stomach problems and passes out. While Nick is distracted with helping Wu, Renard removes the cell phone from Nick's desk before it can be checked into evidence.
Adalind greets her mother, Catherine, at her home. While Adalind isn't happy with the assignment Renard has given her, she still loves him. Adalind comments it's going to get ugly with Catherine retorting, "You do ugly so well." Hank calls, and Adalind is clearly already tired of this game. Adalind explains she can't see him tonight because her mother is in town, yet invites him over for a romantic dinner for two tomorrow. Hank is calling from right outside Adalind's window, stalking her again, and drives away satisfied she's telling the truth this time after seeing Catherine with her daughter.
At the hospital, a doctor explains to Nick the eating disorder pica, which involves consuming non-edible substances. They found coins, Chap Stick, buttons, bottle caps and paper clips from pumping Wu's stomach. While Wu rests, Nick calls Monroe and Rosalee about Hank's intoxicating infatuation with Adalind. Sounds like classic love potion stuff to them. Rosalee mentions many potions go from deeply in love to deeply dead. If Hank and Adalind ever consummate their relationship, Hank may never be cured. Remembering how things go wrong when potions are taken by people they aren't intended for, Monroe and Rosalee deduce Wu has fallen victim to the same potion as well.
During the night, Renard replaces the cell phone sim card that could trace the victims back to him with a new one. Nick is beyond frustrated the next day to find the cell phone data completely useless. Who puts a new sim card in an old phone? Nick talks to the captain about the shooting and theorizes there was a third man who did the crime. Renard appreciates Nick's enthusiasm; however the victims' families are already coming to collect bodies, and with their diplomatic immunity status, they've requested no further police action. Nick is despondent as he is with any case that remains unresolved.
Rosalee uncovers the exact potion used on Hank and is able to create an antidote. Nick, Monroe and Rosalee drop by Wu's apartment to test the cure and find Wu in his underwear grazing on shag carpet. Wu beings to gag once they enter, forcing Rosalee to inert the antidote through his nose immediately as Monroe and Nick hold him down. Wu's body convulses at first, yet when the convulsions subside, Wu comes to and is wondering why everyone is in his apartment... and why is he in his underwear? Now to try the cure on Hank!
Hank heads into Adalind's house and turns off his cell phone. Adalind has decorated the house with lit candles and rose petals in preparation for their romantic encounter. Soon afterwards, Adalind leaves the house in a hurry before Nick, Monroe and Rosalee arrive. They find Hank lying in bed, still alive yet unconscious. Rosalee realizes her antidote is useless now since Hank and Adalind have slept together. Adalind calls Nick to announce Hank will be dead by morning unless she gets the key. Nick agrees to meet Adalind at Forest Park. Prior to Nick leaving, Rosalee reveals spilling the Hexenbiest's blood won't save Hank. It will take the blood of a Grimm.
Adalind is waiting at the park as Nick drives up. Nick admits he didn't bring the key, though that shouldn't stop the two of them from battling... violently. Nick and Adalind struggle back and forth, each trying to get the upper hand. Nick is able to pin Adalind under him and he surprises her with a strong kiss. Adalind responds by biting him and Nick's blood flows into her mouth, immediately starting the process of removing her powers. The Hexenbiest spirit rises from her body, and Adalind is beside herself, irate with Nick. "I'm just like everybody else now. I have nothing." Monroe calls Nicks to inform him the spell is broken and Hank is fine.Adalind goes to her mother's house looking for comfort for the loss of her powers. Instead of sympathy, Catherine slaps her and admonishes Adalind, saying she knew how important it was to get the key. Renard is at the house as well and recognizes he may have underestimated the Grimm, but he also blames himself for trusting an "amateur." They ostracize Adalind who leaves the house truly alone now. Meanwhile, Nick is back at the trailer studying the imprints of the key marks again. What is so important about this key and what can it unlock?