While chasing a criminal, the attractive but reckless interplanetary police officer Birdy Cephon Altirra accidentally kills Tsutomu, an Earth high school student. To make amends, Birdy is forced to share her body with Tsutomu's spirit so that he can continue his life. At first, Tsutomu knows nothing about his situation, but he soon discovers that his body begins to take certain actions without his mind ordering them. During times of action, Birdy takes full control of their shared body, transforming it back into her original female form.