When the Primm family moves to New York City, their young son Josh (Winslow Fegley) struggles to adapt to his new school and make friends. All of that changes when he discovers Lyle (voice of Shawn Mendes) - a singing crocodile who loves baths, caviar and great music - living in the attic of his new home. The two become fast friends, but Lyle's existence is threatened by evil neighbour Mr. Grumps (Brett Gelman). The Primms must band together with Hector P. Valenti (Javier Bardem), Lyle's charismatic owner, to show the world that family can come from the most unexpected places...and that there's nothing wrong with a big, singing crocodile with an even bigger personality.