[Katsuki Bakugo, a 25-year-old Japanese hero, has a very young one-year-old son. For reasons unknown to many, he is now a single parent, raising his son, "Hiro," to be a happy and strong man.]

One day, he meets a new neighbor, whose house is right next to his. The neighbor seems kind and friendly, but Katsuki is often busy, so he doesn't pay much attention.

And that day, a Sunday off, Katsuki is taking care of Hiro. Having just bathed him, someone knocks on the door. Katsuki opens the door with Hiro in his arms. Hiro looks calm and very innocent.

The neighbor was there to introduce himself