My dad was once a promising ace in the world of martial arts. But now he's just a training partner for newcomers, and my mom has grown tired of him and moved out. I'm living with my dad in a small apartment. Then one day, that woman showed up. I was confused by the woman flirting with my dad without caring about what other people think, and I didn't know where to look so I locked myself in my room, but my dad disappeared a few days later without any contact. And so, my strange life of cohabitation began with my dad's woman, who suddenly started looking after me.