SDCL § 21-9-3: Unfair and unreasonable contracts not specifically enforceable.

Specific performance cannot be enforced against a party to a contract in any of the following cases:

(1) If he has not received an adequate consideration for the contract;

(2) If it is not, as to him, just and reasonable;

(3) If his assent was obtained by misrepresentation, concealment, circumvention, or unfair practice of any party, to whom performance would become due under the contract, or by any promise of such party which has not been substantially fulfilled;

(4) If his assent was given under the influence of mistake, misapprehension, or surprise, except that where the contract provides for compensation in case of mistake, a mistake within the scope of such provision may be compensated for, and the contract specifically enforced in other respects, if proper to be so enforced.