Supernatural

There is a Ghost Doctor living by the Lethe River who only treats illness for ghosts. He had only one rule. All the ghosts who wanted him to help must obey three rules: one, swim across the Lethe River, two, tell him their story, and three, leave behind something that belongs to them. No one knows anything about him and no one knows why. The Ghost Doctor is mysterious; no one knows where he came from, no one knows where he’s headed to, they only know that he’s residing by the Lethe River with his rules.