Ever since Mattie Waters lost her mother, she's been sharing a trailer with her aunt Molly, the proud owner of Owl's Outstanding Donuts. The donut shop serves up delicious treats to people driving down California's Highway One. But not everybody is a fan of the shop. When an owl taps on Matties window one night, Mattie looks out to see suspicious activity not far from the shop. A shady duo is dumping gloop near the highway. And soon people want to blame Aunt Molly! With the help from her friends, Mattie sets out to find the real culprits.