S.C. Code Ann. § 1-3-120: Vacancy in office of both Governor and Lieutenant Governor.

In case of the removal, death, resignation or disability of both the Governor, and the Lieutenant Governor, the President of the Senate shall perform the duties and exercise the powers of Governor until such disability of the Governor or Lieutenant Governor has been removed or until the next general election, at which a Governor must be elected by the electors duly qualified, as prescribed by Section 3, Article IV of the Constitution and the general state statutory law.