Jill Pembrey, a geologist, is collecting volcanic rocks on Mt. Hood when a mysterious man attempts to steal her satchel full of samples. Jill pepper sprays him and manages to drive off safely, but she is clearly shaken. Later that night, in her home, Jill experiences what she thinks to be an earthquake, only to realize her home has been invaded. When she investigates the disturbance, a Volcanalis appears out of nowhere and kills her.
The multiple memories of Nick inside of Juliette's head are still manifesting themselves all around her house simultaneously, and it's driving her crazy. Unable to take it any longer, Juliette storms out of her own home and attempts to drive away, but a vision of Nick pops up in the passenger seat. In a moment of hysteria, Juliette crashes her car and is sent to the hospital. The real Nick visits Juliette in the ER, where she tells him to leave her alone. He has to understand she can't see him anymore. Nick, devastated, tries to remain encouraging as he leaves.
At Monroe's, a soccer match is on TV, but Nick can't even focus on the game. His mind is still on Juliette and what she said to him in the hospital. Monroe tries to comfort Nick by saying "at least she wasn't hurt in the accident," but that's hardly the main source of Nick's sadness. It's kind of a unique situation, being forgotten by the love of your life. A phone call from the precinct takes Nick's mind off of things, as he's called to a crime scene. At Jill Pembrey's house, Nick immediately notices the burn marks everywhere, especially on the victim's body; handprints burned onto the arms and neck. Nick finds melted plastic on the table. Whatever happened, it was pretty hot when the crime took place.
In Vienna, Adalind is experiencing morning sickness on account of her pregnancy when someone knocks at her hotel door. It's Frau Pech, and she orders Adalind to get dressed quickly - they have a meeting with Zigeunersprache, the Queen of the Schwarzwald Gypsies. Adalind doesn't want to go, but Frau Pech let's her know if she'd like to know the true value of her motherhood, its time to find out what her little kinder is worth...
Jill's workbag at the crime scene leads Hank and Sgt. Wu to Thom Evan's office at Geo, Inc. He's shocked at the loss of his worker, but he mentions her call the day before about pepper spraying an eco-freak on Mt. Hood. Thom agrees to show them where she was researching on the mountain, and when they go, Thom leads the officers to her research site. When the group comes back to their truck, it's been smashed and vandalized. Nick sees a figure running through the woods and chases after him. Eventually Nick and Sgt. Wu pin the criminal down and arrest him, but not before Nick sees him morph into Taureus-Armenta.
Juliette visits Pilar's house and provides an update on her condition. Nick is everywhere Juliette goes, and she can't take it anymore. Pilar encourages her to drink a special concoction of hers, which will help Juliette with her focus. She needs to hone in on one memory and concentrate on it completely. If Juliette can connect with one moment and really become part of the memory, her condition might improve. When Juliette goes home, she tries out Pilar's technique, and within moments, a vision of Nick arrives, from the time he was moving in with her. She is suddenly transported back into that moment of her past.
Frau Pech and Adalind arrive at the Gypsy camp for their meeting; it is an intimidating place full of frightening sounds, bright lights and shady figures. It is here where Frau Pech introduces Adalind to the Queen, Stefania Vaduva Popescu. Stefania invites them into her home. Inside, Stefania tells Adalind there is only one way to put an accurate price on her baby - and that's by confirming it's royal blood. Adalind promises the baby's authenticity, but Stefania needs to know for sure; her sons pin Adalind down as Stefania grabs an ancient scythe-like utensil, planning to extract a sample of blood herself. Unfortunately, Adalind has to be awake for the procedure.
In Renard's office, Nick and the Captain figure out the man on the mountain is Markus Hemmings, a former archeologist with multiple arrests for assault and property damage on Mt. Hood. Nick tells Renard he's never seen a Wesen like him, and the Captain offers to help. In the interrogation room, Markus denies involvement in Jill's death. He says he's on the mountain against his will, and he fears for the world if the Volcanalis is angry. The Volcanalis killed Markus' wife. It seems this creature kills when people take pieces of the earth from where he rests. Outside, Sgt. Wu finds a correlation of violent attacks connected to people taking volcanic rocks from mountains on the ring of fire. The last person to take rocks was Thom Evans. Renard orders Nick to check on Jill's boss.
Thom Evans is eating dinner alone at home when he hears a mysterious noise. Returning to the kitchen, Thom notices the water in a vase boiling and becomes alarmed. When the lights go out, Thom is attacked by the Volcanalis just as the police arrive. Renard orders the creature to let Thom go, and when he doesn't listen, Renard opens fire. Unfortunately, the bullets disintegrate on impact. The heat of the creature almost debilitates both Nick and Renard, but Nick gains the energy to chase after the creature as it escapes out the window. Unfortunately, it disappears before he can catch it.
Meanwhile, Juliette is still deeply ensconced in her memory of Nick moving into her home. He wants to put his Elvis lamp somewhere in the house, but she convinces him to give it up in favor of her feminine sensibilities. He reluctantly agrees. But when Juliette goes to get him a beer to celebrate the "breakup," she's taken out of her flashback and flung back into the present moment, where she's alone in her house.
In the trailer, Monroe finds information on the Volcanalis. Most of it's in Latin, so they take it to Renard for translation. Renard deciphers that the Volcanalis is far more dangerous than other creatures they've dealt with and asserts they can't fight fire with fire, in this case, literally. The group goes to Markus for ideas. Markus knows the Volcanalis is a force of nature and wants to help, but he thinks hell will freeze over before they defeat the creature. Nick asks Markus what it will take to make that happen.
Back at the gypsy camp, Stefania has proven the blood of Adalind's baby is Royal. Stefania is prepared to offer Adalind 500,000 euros if the baby is a boy, 750,000 if it is a girl. It must be of sound mind and body before she buys it. Frau Pech thinks they can get that on the open market in Budapest, but Stefania isn't confident they could even make it to Budapest. It sounds like a threat. Adalind isn't interested in money, though. She wants what the Grimm took from her... she wants her powers back. Stefania doesn't know if that's possible, but when Adalind threatens to abort her baby, all the leverage is on her side.
The group decides to get the Volcanalis' attention by stealing a ton of rocks from Mt. Hood. At an abandoned warehouse in Portland, Markus dumps the rocks in the middle of the room and stands next to them as bait. Nick, Renard and Monroe set up three tanks of liquid nitrogen with hoses and wait in the darkness. Suddenly, the Volcanalis arrives, hell-bent on destruction. Before he can get to Markus, Nick and the others shoot liquid nitrogen at him and freeze him to death. The creature turns into solidified rock, and Markus takes a sledgehammer to the remains in the name of his deceased wife.
Juliette's focus on one memory with Nick has reignited feelings she once had for him. She remembers what it felt like to love Nick. At home, Juliette takes a framed picture of the two out of a chest and places it on display. When she finds the ring Nick offered her when he proposed, she once again is transported back to the moment he popped the question. When Nick asks her to be his wife, Juliette looks on in the present moment, and in her flashback, though she doesn't provide an answer...