In 19th-century Saint Petersburg, young Sasha watches with a heavy heart as her beloved grandfather, the renowned explorer Oloukine, embarks on a daring expedition to the North Pole aboard the Davaï, an icebreaker specially crafted to brave the unforgiving Arctic conditions, funded by the Tsar of Russia. After years of silence regarding the vessel's fate, the Tsar announces a generous reward of 1 million rubles for any evidence of the Davaï's final location, effectively declaring it lost with all crew members.
Fast forward to Sasha's 15th birthday, where she is about to kick off her debutante ball. Eager to connect with her grandfather's legacy, she sneaks into a new library wing dedicated to Oloukine's contributions, but overhears Prince Tomsky disparaging her grandfather's legacy. Tomsky views Oloukine's disappearance as a political embarrassment for the Tsar, threatening to strip the explorer's name from the library. During her ball, Tomsky puts on a show of indignation when Sasha reminds everyone of her grandfather’s notes indicating a different route than what the Tsar’s advisors believed. The gathering quickly turns against her, further isolating her family. Following this debacle, Sasha's father, who was denied an ambassadorial position in Rome due to Tomsky's scheming, unfairly directs his frustration at Sasha for their family's diminishing stature.
Determined to restore her family’s honor, Sasha runs away, venturing to the coast where she discovers a vessel named the Norge, outfitted with a reinforced hull that suggests it is capable of navigating the treacherous northern oceans. After negotiating for passage with Larson, who falsely claims to be the ship’s captain, she watches as the Norge sets sail without her, forcing her to toil in a local tavern while waiting for its return. Upon the Norge's arrival, Sasha successfully leverages her grandfather’s notes to convince the actual captain, Lund, that she can locate the Davaï, allowing Lund and his crew to qualify for the enticing Tsar’s reward. Bound by a sense of honor and family loyalty, Lund agrees to take Sasha on board since Larson, his first mate and sibling, lost her fare in a gambling spree during their last ill-fated voyage.
As they traverse the Arctic, the crew initially warms to Sasha, but when misfortune strikes — leading to the destruction of the Norge due to Larson's inexperience — their camaraderie fades, and tensions rise as dwindling provisions drive the crew to accuse Sasha of their plight. As despair deepens during their arduous journey, Sasha flees into a harsh blizzard, where her loyal husky companion guides her to an unexpected discovery: the frozen remains of her grandfather, Oloukine. Retrieving his logbook, she learns that Oloukine's quest mirrored her own, as he too had been abandoned by his crew on the ice-locked Davaï, driven by an obsession to reach the North Pole. In a poignant moment, she finds a snapshot of her younger self resting on his desk, frozen in time.
Armed with the coordinates from her grandfather’s log, Sasha leads the crew back to the location of the Davaï, where they courageously use dynamite to liberate the vessel and bring it back to the sea. As the credits roll, the visual narrative unfolds, showcasing the Davaï’s triumphant return to St. Petersburg, Tomsky's public shame as Sasha's discoveries validate her efforts, and an emotional reunion with her father. In a touching post-credits scene, the flag planted by Oloukine at the North Pole is caught in the polar breeze, symbolizing his enduring legacy.
