日历女孩Helgoland is set in 2034 after after a global apocalypse, where the North Sea island of Helgoland has become humanity's last safe haven. A totalitarian society has been established that only allows 513 people on the island and as resources are scarce, an inhumane 'social ranking' system evaluates the lives of the inhabitants according to their 'usefulness.' At there same time, a dangerous force from the mainland prepares to invade.