This story tells about twins named Hayakawa Ukyou and Narisawa Sakyou. Sakyou likes to wear girls clothing, meanwhile Ukyou stays with her parents and is very tomboy! Sakyou finally moves back to Hayakawa residence temporarily before he had to go to US, but he still wears skirts and stuff, even to Ukyou's school!

Sakyou had an allergy towards the female gender. He may either drop unconscious or explode when a female holds him. Ukyou is an exception. So, Sakyou finally had to go to US. After he left, Ukyou find out that he will be back sooner than she thought! With an extra baggage called Karl Evans, a prince of the Guten Tag kingdom who gave him (he didn't know Sakyou is a boy) an ultra-expensive and precious ring!

Sakyou convinced Ukyou to switch their identity, this ended up to a complicated situation involving the ring, kidnapping, and monarch business. What will happen between this three?