Chapter 1: Buster's Big Break?

After the events of Sing 2, the Moon Theater gang have been a big success! Once their latest show (Out Of This World) had been on tour, everyone fitted into their roles. Everyone except Buster, though.

Even though his friends' talents have struck it big on stage, he'd always wonder if he could join in on their fun, and not just be on the sidelines, watching them make magic happen. But that all changes when one night (before a show), Gunter reworks the show's plot by adding a new planet, and Ash invites Buster to sing and dance with her in the show!

As she, Gunter, Rosita, and even Clay Calloway help him through his big moment on stage, Buster shows his friends that even he, just like them, can be a star!