A partnership develops between extroverted musician Austin (Ross Lynch) and brilliant but shy songwriter Ally (Laura Marano). In the opener, Austin records one of Ally's songs and becomes an Internet sensation, which leads to the two teaming up to write and record together.

Ally loses her songwriting book, which also contains her secret diary. Unfortunately, Austin and Dez find it first and learn Ally has a secret crush, and Austin is convinced that it's him.