(from ebookjapan):

This is a poignant jidaigeki manga about Super Manbe, a skilled samurai with a strong sense of justice and a kind heart, who goes on an unusual journey to exterminate a group of villains.

Manbe subdues a rampaging horse with his bare hands and then makes the acquaintance of Senkichi, a horse boy who hates samurai. Later, Senkichi's horse is almost taken by the arrogant samurai Shigebei Nagashima, but Manbe rescues him...?