Suzume, a 17-year-old girl who lives in a quiet town in Kyushu, encounters a traveling young man who tells her "I'm looking for a door." She follows after him and discovers a weathered door in the ruins in the mountains, as if it were the only thing left standing from a collapse. As if drawn by something, Suzume reaches for the door...

Before long, doors begin to open one after another in various parts of Japan. As disasters come from the far side of the doors, the open doors must be closed.

The stars, the setting sun, and the morning sky—in that place she wandered into, there was a sky that seemingly blended all of time together. Guided by the mysterious doors, Suzume's "door-locking journey" begins.