This is the second film in the Lone Wolf and Cub series, directed once again by Kenji Misumi and starring the great Tomisaburo Wakayama. While wandering through the wilds of Japan with his 3-year-old son, Daigoro, (Akihiro Tomikawa), the assassin-for-hire Ogami Itto finds his next assignment: He needs to kill a merchant intent on revealing corporate secrets. On his tail, however, there’s a trio of female assassins who have been sent to kill him and his son.

The film opens with a fighting scene where Ogami is under attack by two Yagyū, the first of whom has a sword slammed into his head and down the middle of his forehead, while the second is impaled mid-air with a naginata assembled from parts of Daigoro’s cart.

In this film we can already see an evolution of style and genre. Little Daigoro is more active, plays pranks, acts like a child and no longer like a baby, in addition to understanding in a more lucid way the bloodthirsty role of his father. Part of this father and son's journey of survival is also punctuated by their actions. In some fights he even participates, albeit briefly. When Ogami is wounded in battle, Daigoro helps nurse his father back to health in time for a second sword fight.

The “River Styx” in Japanese Buddhist mythology is the Sanzu, which must be crossed by one of three increasingly dangerous paths before a soul can enter the afterlife. The path is determined by the individual’s load of sin.