Supapunpinyo plays a high-schooler named Min, who dies—and is already in the morgue of a hospital—before being brought back to life. The only thing is, it's not actually Min who returns, but the wandering spirit of a different person who was given a new chance at life by someone called the Guardian (Nopachai Chaiyanam). But much like a homestay (where someone stays with a local during a trip), the new Min's body is also temporary. He has to figure out who killed the old Min within 100 days or else lose his newfound family, friends, and love.