A parenting diary of assassin buddies?. Two assassin partners Kazuki Kurusu and Rei Suwa who never let their target get away somehow end up taking in a four-year-old girl Miri.

After he witnesses his father’s murder at the family dojo, Ryo Hazuki dedicates his life to finding the man responsible — a mission that takes him from the streets of Yokosuka, Japan to the sprawling metropolis of Hong Kong, and beyond. Soon he’ll learn that larger, mystical forces are at play as he trains to become the ultimate martial artist in his quest for revenge.