Josh Gordon and Will Speck direct this musical comedy adventure based on the children's books by Bernard Waber. Shawn Mendes provides the voice of Lyle, a crocodile who lives in the attic of a New York home and loves to sing but suffers with terrible stage fright. Lyle's owner Hector P. Valenti (Javier Bardem) is forced to leave the home and the Primm family move in. When Josh Primm (Winslow Fegley) discovers Lyle in the attic, the two become friends. Lyle wins over Mr and Mrs Primm (Scoot McNairy and Constance Wu) but their downstairs neighbour Mr Grumps (Brett Gelman) is annoyed by all the noise and begins to investigate. What will happen when he discovers Lyle?.