Duke Fastener rules the planetary kingdom of Hookland, sometimes known as Berryland. Despite his title of Duke, he is the planet's sovereign. His fascination with space exploration leads him to dispatch the robot Ticktackbon to Earth for strawberries, an action that accidentally brings his niece to Hookland. Intending to pursue his interstellar ambitions, Fastener delegates royal authority, appointing his niece as temporary regent. This decision sparks the central narrative as his niece assumes the unexpected role.

A critical health condition afflicting Duke Fastener becomes pivotal, compelling his niece to undertake a vital quest for his recovery. Her journey ultimately results in her securing the throne of Hookland, ensuring the kingdom's continuity. With the succession established, Duke Fastener departs to fulfill his dream of traveling among the stars.