One who obtains a thing without the consent of its owner, by a consent later rescinded, or by an unlawful exaction that the owner could not at the time prudently refuse shall restore the thing to the person from whom it was obtained unless the person has acquired a title to the thing superior to that of the other person or unless the transaction was corrupt and unlawful on both sides. The restoration required by this section must be made without demand except where a thing is obtained by mutual mistake, in which case the party obtaining the thing is not bound to return it until the party has notice of the mistake.
§ 27-1-713, MCA