Joe's murder shakes loose everything he spent years burying. The first four episodes burn through so much visceral animation that when the quality collapses, it feels like watching a different show entirely, one that rushes to finish what it started. This is a revenge arc with elite fight choreography in the first half, then a scramble to the finish line in the second.

Joe Logan lives quietly in the American countryside with his wife and child, under a false identity that hides his past as a ninja who fled his clan. That peace ends one night when assassins from his old organization attack, killing his family as punishment for his betrayal and leaving him for dead. Joe wakes in a hospital, unsure how he survived. When the killers come for him again, he is ready, and he takes back his former persona, Ninja Kamui. With help from two police detectives investigating the murders, he sets out for revenge against the clan that raised him, pitting old ninja skills against high-tech weapons, cyborg fighters, skilled killers and other ninjas.