Yankee big man, protect my dream! Reimu is a girl who can control her dreams as she pleases, she has created a dream room filled with cute things and enjoys playing there every night.

For Reimu, who is unable to get along in the real world, dreams are the only place where she can feel at home. One day, however, a vicious monster appears in her dream and begins to rampage.
Reimu summons Kota Ara, a yankee she sees on the street, and tries to fight the monster.

A dream battle between a girl and a Yankee begins in order to protect a precious dream!