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