After a life-changing incident, timid college student Koichi Haimawari accepts an offer from revered vigilante Knuckleduster to train as his protégé.

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.

After he witnesses his father’s murder at the family dojo, Ryo Hazuki dedicates his life to finding the man responsible — a mission that takes him from the streets of Yokosuka, Japan to the sprawling metropolis of Hong Kong, and beyond. Soon he’ll learn that larger, mystical forces are at play as he trains to become the ultimate martial artist in his quest for revenge.