Subaru, a sixth grader with little pocket money, obtains Akuma Pay, a mysterious app that can buy anything. After he and his friends indulge in its luxuries, they face a demon's contract demanding their bodies in payment and must enter a game that puts their lives at stake.

The price of an app that buys anything is your life.

Momoko Torikawa, a sixth grader and the daughter of a yakitori shop owner, is tired of her name but is a devoted fan of MC Missile from the junior-high HIPHOP group NYKID. Writing lyric diaries in secret as MC Torimomo, she learns a secret about Missile's birth and enters a rap battle to choose NYKID's new member.

The daughter of a yakitori shop takes the rap-battle stage, finding her own voice in a story full of humor and exhilaration.