Their world is on the brink of collapse. Unfortunately, they summoned Isaak.

Isaak wakes up in a cold panic after a fatal accident. Seven bizarre witches have summoned him to their dying world, but they don't want his help. They want his mana.

These seven sisters have learned that they can obtain immense power if they enter into covenants with humans from other worlds. Unfortunately, they only had enough mana to summon Isaak, and each sister would sooner destroy Isaak than allow him to power up a sister other than themselves.

Caught in the middle of their fatal family drama, Isaak will need to learn the rules of this new world fast. Because he was not granted any special powers by a Goddess, and he did not wake up with any unique [skills]. His only boon is the reluctant protection of his powerful summoners who do not want him dead. Yet.