Gizmo Tinker is a messy haired unicorn with a broken horn living in the Nuts and Bolts workshop with her brother, Rust Bucket. She lives for inventing, whilst Rusty is just a simple mechanic/engineer. Together they run the Nuts and Bolts workshop, Rusty playing Mr. Fix-it out front, and Gizmo inventing her contraptions in the back. They led a pretty normal life in the town of Hoofington, that is until "Sprocket" came to be.