Casey (short for Acacia, but don't call her that) is spending a few summer days with her parents at Disneyland. Just like they do every summer.

Except this summer is different.

Casey's best friend has dumped her. She starts high school in the fall, and she's tired of following her parents' rigid schedule and putting up with their embarrassing behavior. She's miserable. Even Disneyland can't make her happy.

Then, standing in line for the Indiana Jones Adventure, she bumps into Bert. A year older. Tall. Brown eyes. Nice. But Bert's parents are mysteriously absent. And he wears an old, broken Mickey Mouse watch. Bert has secrets.

When Casey ditches her parents to run off with Bert, those secrets are revealed in the darkness of a Haunted Mansion Doom Buggy, aboard a rocket ship hurtling through Space Mountain, and in the cramped confines of a Matterhorn bobsled.

Is Bert really as cool as he seems? Could he become Casey's first…boyfriend?

To make matters worse, Casey must also fight off her parents' attempts to ruin her relationship with Bert and fend off a pack of selfish, rowdy girls - the “Bra Strap Girls” - who seem intent on sabotaging her vacation and stealing Bert.

Casey can't stay in Disneyland forever. When she leaves, with or without Bert, she'll have left behind her childhood and learned some important lessons about what it means to grow up.