A mysterious mugging happened in Tokyo. The victim was Sagi Tsukiko, the designer of the incredibly popular toy Maromi. Tsukiko’s testimony is that the attacker was a young boy on rollerblades swinging a bent golden bat but many suspected Tsukiko to have knocked herself out. The reason was that the attack came at a convenient time when her boss was pressuring her to come up with the next groundbreaking design.

Soon after, the next victims appear, all of them going through some sort of crisis in their lives and their testimonies always involve "Shounen Bat", that young boy with the golden bat…

Who is this "Shounen Bat"? Who’s his next target?