A man is transported through time and space to a special starship, where he and 12 other people must work out what happened.

A certain song transports a boy named Sorata Suzuhara to a different era and place. Sorata finds himself standing in an unfamiliar place: an old town, awash with sepia tones. In this world, he meets three young ladies and nine young men and joins them on a journey aboard the mysterious Norn ship, a giant globe that floats in midair.