In Ambrette Town, our heroes run into the journalist Alexa, who’s working on an article about an amazing discovery at the Fossil Lab. She invites Ash, Serena, Clemont, and Bonnie to come with her, and they all check out the lab’s collection of fossils from Pokémon that lived long ago and are now extinct. The fossils aren’t the amazing discovery, though—the researchers take our heroes into a special frozen habitat inside the lab, where they meet a living Amaura and Aurorus that were restored from fossils discovered in the ice!
After they leave, Team Rocket swoops in to steal Amaura for the Boss—which is a big problem, because Amaura grows weak if the temperature is too warm. But Aurorus is able to track Amaura through its cries, which create an aurora in the sky, and it leads Ash and the others straight to Team Rocket. The villains are defeated, Amaura is rescued and brought back to the lab, and everyone celebrates the victory with a giant snowball fight!
Ash trains outside with Froakie and Fletchling. Froakie's Water Pulse is evaded by Fletchling's Double Team, but Froakie's Bubble hits it. But even after the blow Fletchling remains upright. Ash praises both for a job well done when Alexa, along with her Helioptile, walks onto the battlefield. She notices Serena has decided to accompany Ash and his friends on the journey, while Helioptile plays with Dedenne and Pikachu. Alexa tells the group she came to collect information for an article, and heard from Viola that Ash was going to challenge the Cyllage Gym. Alexa is writing an article about the famous Ambrette Town Fossil Laboratory, who recently made a new discovery. The group is excited about this and decides to join her.
At the laboratory, the group meet Thaddeus, a researcher. Team Rocket watches from behind a bush, curious, and send a flying camera to follow the group inside the lab. Inside, the group takes a look at many fossils of ancient Pokémon, but Serena is not impressed. Thaddeus then leads them down a hall and tells them to put on snow jackets before they go into the next room, which is a freezer room that is kept at a cold temperature for the Pokémon that live there. Ash slips on the ice and is approached by an Amaura, an extinct Pokémon that was said to live in a cold part far in the north of Kalos. It is soon joined by an Aurorus, its evolved form. Thaddeus explains that the Laboratory's excavation group discovered parts of the Pokémon frozen in ice, and were able to restore them. Having lived in a region with few predators, the Pokémon are friendly, and Amaura nuzzles the visitors. By the time Alexa begins to interview Thaddeus, Team Rocket's camera has recorded everything. Outside, Team Rocket watches the footage and decides to capture both Pokémon.
When the group leaves the freezer room to get warm, Team Rocket breaks in and pretend to play tag with Amaura to lead it outside and into a waiting truck. James and Meowth return to capture Aurorus. When the giant Pokémon proves hard to budge and begins wailing, the others hear and rush back inside. Team Rocket decides to flee with only Amaura, and drive off. While the other researchers try to calm Aurorus, Thaddeus explains that this could turn out bad since Amaura is weak to heat and temperatures it's not used to. Inside the truck, Amaura uses its aurora bond to communicate with its parent Aurorus, who heads out of the freezer room, followed by the researchers. Thaddeus explains the auroras appear when Amaura lets out its cry really hard. Aurorus follows it, with Ash, his friends, and Alexa in pursuit. In the truck, Team Rocket notices the cold being emitted from Amaura and turn on the heater. The high temperature weakens Amaura even more, and far behind the group notice the aurora start to fade as Amaura starts to lose energy.
Along the road, Team Rocket's truck gets a flat tire, and they stop to change it. Alexa and the group meanwhile notice a fork in the road and they don't know which way to go. Aurorus then calls to Amaura this time, and the aurora grows brighter again as it responds. Aurorus freezes the river before them and the group crosses. Soon they have reached the truck, as Amaura grows weaker and weaker. When Team Rocket refuses to give up Amaura, Clemont sends out Chespin to face James's Inkay. Chespin hits Inkay with Pin Missile, while Serena, Bonnie, and Alexa go to the back of the truck to get Amaura, but are stopped by Meowth. Serena sends out Fennekin who uses Hidden Power, but it is blocked by Meowth's Fury Swipes. Just then, Aurorus appears behind them and freezes Meowth with Blizzard, allowing the girls to reach Amaura, who is in bad condition. They tell Ash to hurry, and he tells Pikachu to use Thunderbolt. But Wobbuffet reflects it back with Mirror Coat. Aurorus takes the blow however and uses Blizzard to freeze Team Rocket. Then a Thunderbolt from Pikachu blasts Team Rocket off for good. Once outside the truck, Amaura collapses. Aurorus curls around it to cool down its temperature. Amaura's health is soon restored. Just as the group decides to get the Pokémon back to the laboratory, Thaddeus's truck pulls up and takes them back.
Back inside the freezer room, Amaura has healed completely and nuzzles all the group. The group and the Pokémon play in the snow together, and Alexa now has plenty of material for her article.