to sing “Rudolph the Red-Nosed Reindeer.” A year later, while he was recovering from vocal cord surgery in 2016, Bublé shared a video of his niece Jayde beautifully singing a cappella.

He forms a study group with the other members of the cast, and they all become lifelong friends as they go through increasingly wacky experiences—whether it’s a school-wide paintball game, meeting up ...