After losing her parents in a car accident, Okko goes to live with her grandmother, who runs a traditional Japanese inn built on top of an ancient spring said to have healing waters. Okko discovers there are spirits living there that only she can see; not scary ones, but welcoming ghosts who keep her company and play games. The inn's motto is that it welcomes all and rejects none, and it is soon put to the test as a string of new guests challenge Okko's ability to be a gracious host.