Tetsuya, a young yakuza, returns to his family after his adoptive father is wounded in an attack from a rival gang. In his battle against dishonorable enemies and corrupt yakuza politics, he makes an unlikely ally in a rebel cop.

Hattori-kun received a letter from Iga's father asking him to take his friends and return home for spring break. Hattori-kun leaves for Iga with his younger brothers Shinzo, Kenichi, Yumeko-chan, and others. However, a suspicious shadow stares at the group... He is a subordinate of the scientific ninja Mechamaro, who has replaced the power of ninjutsu with the power of science. Mechamaro was plotting to confront Hattori-kun in order to prove the strength of scientific ninjas. And in order to occupy Iga no Sato, Hattori-kun sends a fake letter...

Seventeen year old Tetsuya kills the boss of a rival gang with the promise of being made. After seven years of prison, he discovers that he is all but forgotten by his Family. The two rival Families have reconciled and Tetsuya was been discarded to keep the peace. Wanted what he was promised, Tetsuya becomes a one-man path of destruction, only to be betrayed once again…