An older brother and his little sister find themselves being adopted by Principal Celestia after meeting a strange man promising them a parent. Turns out there was way more included in the deal than the two siblings had actually expected...
Saitama wakes up bored one day, only to find a portal in his room. Being Saitama, he walks straight through it. In the new world, he meets a young filly name Lily Longsocks who is as strong as he is. Of course they get into a fight.