[1] It is initially set in Japan following the end of World War II and follows the story of Nicholas Linnear, a man raised by Anglo-Chinese parents.

As a youth, Linnear is introduced to the world of aikido, kenjutsu, and iai-jutsu at a local dojo of the Itto Ryu also attended by his cruel and violent older cousin Saigō.

The ninja are introduced not as magical or almost mythical people, but rather as supreme martial artists who have reached the highest level and seek to progress further.

It is suggested that by becoming ninja they strive to advance to an even higher plane, gaining skills such as haragei, or sensing the surrounding world in a different manner.

This peace is shattered when a prominent local businessman is murdered in an extremely unusual manner (by a poisoned ninja shuriken).

Linnear quickly realises that a ninja is the murderer and the next target is his new girlfriend's father, Raphael Tomkin, for whom he begins working as a bodyguard, although not without persuasion.