On Christmas, Scrooge takes the kids to visit Mt. Neverrest, a mountain of which's peak that is reputably unreachable. When the group arrives, Scrooge is flabbergasted to find the mountain has become a commercial tourist destination. Only Scrooge and Huey are looking forward to exploring the mountain while the rest of the group are keen about the resort; a salesman lies to Launchpad of an "ice fever" to con Launchpad into buying goggles and other equipment for protection, while Dewey buys a sled for Webby to use on the trip. Realizing there is no treasure to be obtained at the top, Louie immediately foregoes the trip and resigns himself to the resort.
The trip proves to be tricky, as the trail up the mountain somehow sends the group back the way they came. Scrooge is determined to make his mark on the mountain, despite Launchpad getting blown back down with the group's supplies. Launchpad ends up landing back in the resort's hot springs. Due to his goggles fogging up from the steam, Launchpad believes he is suffering ice fever and wanders the resort disoriented, much to the irritation of the tourists.
The group seeks refuge inside a cave when a snowstorm develops. Once inside, the opening to the cave somehow disappears and the group is trapped. Huey uncovers the remains of George Mallardy, the first and only climber to make it the farthest up Mt. Neverrest at the cost of his life seventy-five years ago. A vindictive final message left by Mallardy directed to Scrooge forces Scrooge to confess that he was Mallardy's partner on the expedition. On that fateful trip, Mallardy demanded Scrooge release their emergency supplies and money to continue their climb upward, and when Scrooge refused, Mallardy betrayed the young millionaire by cutting Scrooge's rope and making the climb up without him. Huey is furious that their journey is just Scrooge's shot at revenge towards Mallardy until Webby finds a way out of the cave to where they started.
Back at the resort, Launchpad stumbles across Louie who quickly discerns Launchpad was scammed by the salesman. He confronts the salesman with Launchpad to show tourists what the salesman's products did to Launchpad. The salesman unwittingly slips that the ice fever isn't real, and he is exposed as a hoax to the angry tourists.
Scrooge and the others finally reach the peak of the mountain, but at this point Huey has had enough of Scrooge's recklessness and advocates the group return to the resort. As Scrooge and Huey argue, Dewey and Webby try out their sled when the mountain suddenly starts rumbling and the two fall down from the peak. A moment later, Dewey and Webby appear back on the peak's base. Huey realizes that Mt. Neverrest actually has dimensional portals scattered around its surface sending whoever entered into random locations; these portals were sending the group back and forth on the trail. Excited, Dewey and Webby move through the portals to recover their sled. But as they move, the ice becomes less stable. Scrooge tries out a portal and is brought next to the top of Mt. Meverrest. To his dismay, another portal prevents him from reaching the top, so Scrooge enters a fit. The mountain becomes further unstable until Huey persuades him to let go of his pride and leave the mountain. Finally convinced, Scrooge retrieves the sled as the mountain peak starts collapsing. The group rides down on the sled to escape the snowfall on their tail. During the ride, they enter more portals until they finally reach the resort where Louie and Launchpad are. Huey apologizes to Scrooge about failing to reach the top, but Scrooge lets it go and remarks that there's always other adventures that Mt. Neverrest won't compare with.
After Huey discards his map to regroup with the others, the wind carries it to a portal nearby. At the peak of Mt. Neverrest, Huey's map appears from one of the portals and lands perfectly on the top.
- David Tennant as Scrooge McDuck
- Danny Pudi as Huey
- Ben Schwartz as Dewey
- Bobby Moynihan as Louie
- Kate Micucci as Webby Vanderquack
- Beck Bennett as Launchpad McQuack
- Carlos Alazraqui as Salesman/Tourists/Hot Tubber
- Mount Neverrest is a nod to Mount Everest.
- When Scrooge mentions Santa Claus is not allowed in his home, it is possibly alluding to the triplet's story in Mickey's Twice Upon a Christmas, "Christmas: Impossible".