After witnessing a murder, 13 year old Seven Miller has awoken on floor B7 of an underground facility the building has one psychopathic killer residing on each level, and on each floor, it has been designed for them to cope with their trauma. On B6, a serial killer by the name Zack Foster, B5 Danny Victor, B4 Jason Williams, B3 Sarah Roberts, B2 Cal Andrews, & B1 is Seven herself unknowingly. She has an adopted daughter named Nessie who is kept in Cal's level and he is keeping a secret from the known about her. Zack and Seven will team up, she gets him out of here, her and Nessie will leave this place unharmed, and he'll make sure to keep that promise... She will too...

Inspired by Angels of death, please go check out the anime