S.C. Code § 27-27-70
In any action for the recovery of lands and tenements, whether such action be denominated legal or equitable, the defendant who may have made improvements or betterments on such land, believing at the time he made such improvements or betterments that his title thereto was good in fee, may set up in his answer a claim against the plaintiff for so much money as the land has been increased in value in consequence of the improvements so made and the defendant may also set up a claim against the plaintiff for so much money as the land has been increased in value in consequence of improvements or betterments made by any person under or through whom he claims, if it be shown that the defendant actually believed he was taking a good title in fee simple thereto at the time of the alleged taking thereof.
S.C. Code § 27-27-70