A team of assassins exacts a bloody retribution on Joe Logan – a former ninja who escaped his clan – and his family for betraying their ancient code. Rising from his seeming "death," Joe will re-emerge as his former self – Ninja Kamui – to avenge his family and friends and bring down the very clan that made him.

It's a showdown for the ages as the legendary hero takes on the corpse god necromancer, but when the dust settles, something isn't quite right... In the final moments of their epic confrontation, the corpse god's final gambit shot was wholly unexpected -- reincarnation magic! Across space and time, a boy named Polka Shinoyama awakens feeling...not quite himself...... Who could've expected that the climactic battle between good and evil would turn out like this??

Hachimitsu Academy, once an all-girls school, has become co-ed, and teen Kiyoshi is one of five boys to enroll. When he is caught peeping, Kiyoshi is sent to the schools prison, where his punishment is carried out.