Follow the friendship between the Nobara family's pet dog Shiro and a "small dinosaur". Their connection helps the growth of Shinnosuke and the Kusakabe Defense Squad.

One day, a woman named Chiyome Hesogakure with a child named Chinzō visits the Nohara family and claims that she is the real mother of Shinnosuke and takes him away to a Ninja Village. In the ...

When the five visit a private academy, Kazama is attacked, and left with reduced intelligence and strange bite marks.