Seth and his best friend, his dog Mac, live in a house attached to a lighthouse. They often go on fun adventures together discovering mysteries which they are determined to solve. In "The Ghostly Ship" they solve the mystery of the disappearing ship. Seth and his best friend, his dog Mac, live in a house attached to a lighthouse. They often go on fun adventures together discovering mysteries which they are determined to solve. In "The Ghostly Ship" they solve the mystery of the disappearing ship.