The story follows Erika, the princess of the Magic Kingdom, as she searches for a human girl who looks exactly like her. After descending to Earth, Erika finally finds Himeko Nonohara, a tough tomboy. Erika wants to give Himeko a magical device she made to prove her worth as heir to the throne. The device is a hair ribbon that lets the wearer transform into anyone they've seen before, and Himeko is tasked with testing it to see if it works. The plot explores Himeko's adventures and her romantic relationship with Daichi, who discovers her hidden secret.