So the story starts from the introduction this is the main character Whose name is Mr. Satan and his family consists of 6 members
He, his younger brother Yami, his parents Asahi Yamazaki and Mito Yamazaki
Grandparents Rin Yamazaki and Grandma Akihiko
They live on a small island
And to travel they have to take the help of hot air balloon
And a new hot air balloon agency just opened
But that agency isn't normal
The owner of that agency is a mastermind killer
He made the hot air balloon larger so that one of his employees can hide in the balloon
As soon as they are 700m high the worker of that agency comes out and loots their client then murders him if he were to be rich
And when the client doesn't return and their family member asks about them they tell them that he got lost in the town
They did this business for a long time
Then one day , one of the main characters cousins goes to that agency
While roaming around he finds one of the dead spots in the wall
From there he listens
The employees and owner speaking about him
He heard that.....