When Nick returns from his morning jog, Juliette notices he's not sweating. But there are more pressing matters: her friend Alicia called her in a panic because her husband Joe beat her again. She's officially decided to leave him and crash at their house for a few days.
Nick questions Alicia as she walks in the door - Joe doesn't know where she is, right? Alicia assures him he has no idea. She dissolves into tears, morphing into a mouse-like Mauzhertz. Well, things just got more complicated.
In Austria, Adalind and Renard meet in a cafe, feigning warmth towards each other. Catching her off guard, Renard slyly accuses her of being pregnant. Everyone's concerned about the royal baby, but they're leaving her by the wayside. She's isolated from everyone in her life, so there may come a time when she needs a friend like Renard.
Meanwhile, back in Portland, a young cancer patient sits in front of a Russian healer named Boris Myshkin. As he places his hands on her head, his eyes glow green and his skin becomes transparent. Stumbling away from the girl, he asks whether she feels better yet, because her cancer is gone.
Later that night, Myshkin and his wife, Olga, attend a private party where Myshkin is the guest of honor. Drunk and rowdy, he encourages his groupies to drink more. Exhausted from the healing, Myshkin retreats to the storeroom to recuperate. Suddenly, he's attacked from behind, but Myshkin's clearly had training. Turning the situation around, Myshkin grabs the hit man's wrists and morphs into Wesen form. The man screams and rolls out the window, Myshkin's powers have already begun working on him. The hit man stumbles into his hotel room, collapsing on the floor as massive blisters form all over his body.
Later that night, Hank and Nick investigate a dead waiter, stuffed in the freezer without his uniform. Did someone kill him just for his clothes? The venue owner, Dmitri, gives the police the party thrower's name and number. Surveillance footage shows a man strategically carrying a box and entering the storeroom with Myshkin. In the tapes, Myshkin saunters back to the party like nothing happened...
Barely alive, the assassin calls his accomplice and reports, "I don't know how, but he killed me. I love you." The scene shifts to Myshkin's wife, Olga, crying and holding her cell phone. She morphs into a Volk Oxotnik, a fearsome Russian wolfhound Wesen, with murder in her eyes.
Hank, Nick, and Renard interrupt Myshkin during a healing. Nick sees the full power of Myshkin's Wesen form, unbeknownst to him. When they question Myshkin and Olga, the two discuss in Russian their distrust of the police. Apparently, Renard spent time in Moscow and understands them perfectly. Portland police are vastly different than Russian police, he assures them. Myshkin finally answers that he doesn't know who tried to kill him: maybe a failed healing or a jealous lover?
Nick, Hank, and Monroe sift through ancient Grimm documents for an English version indicating what Myshkin might be. Monroe uncovers a 1916 telegram describing Koschie, a Wesen with the twofold power to heal and kill. Renard's contact reveals Myshkin was an assassin before he was a healer. He murders through severe radiation poisoning, but no one understands the nature of it. How do you know if you'll be healed or poisoned?
An unfortunate hotel maid discovers bloody and blistered assassin, Alex, lying dead in the bathtub. The police quickly locate the murdered waiter's uniform - that's one form of justice. Suddenly, Hank finds himself tackled by the "dead man!" Naturally, the hazmat team storms in a few seconds too late to warn the officers of the radiation poisoning. As they're decontaminated, Nick, Hank, and Wu reason that Alex must have received the radiation while in the storeroom. Sure enough, the storeroom is "hot."
Myshkin is brought in for questioning and morphs once they suggest his involvement. Ah, he understands that Nick is a Grimm now. Yes, he once was an assassin for the FSB, but is now paying penance for his crimes by healing.
Alex is awake and whispers his intentions to Renard: Myshkin killed his father, so he was going to kill Myshkin. Now that he failed, Myshkin will murder an unknown "her" as well.
Myshkin sneaks up behind the maid, Larissa, and suggests making a scandal. She seductively agrees, leading him up the stairs as he swigs a bottle of vodka. He only pauses for a second when he catches Olga's eye.
In the bedroom, Larissa urges him to finish the vodka. With the bottle half empty, Larissa's real intention comes to light. She poisoned him via the vodka, but he's still alive! She reveals that she's Alex's sister and Myshkin killed their father ten years ago. Now her brother is gone at his hands as well. Myshkin stumbles out with a knife in his chest just as Nick and Hank arrive. Olga morphs and slashes Larissa's neck with her tusks. Paying penance until the end, Myshkin heals Larissa, even though it costs him his own life.
Exhausted from work, Nick is happy to hear Alicia's turned her phone off. Joe's call to the house demanding to know Alicia's whereabouts cuts the celebration short. Unbeknownst to them, Joe lays in wait outside the house, morphed in his Wesen form.