Certain people suffer from a mysterious disease which causes a wind-up key to appear somewhere on their body. The key has to be wound regularly, otherwise they will stop moving. Miku’s parents, who s...more

Certain people suffer from a mysterious disease which causes a wind-up key to appear somewhere on their body. The key has to be wound regularly, otherwise they will stop moving. Miku’s parents, who suffer from this disease, are captured by the authorities, while Miku escapes into the town to seek help from a mysterious boy called Kuro.