Mo. Rev. Stat. § 290.527
Any employer who pays any employee less wages than the wages to which the employee is entitled under or by virtue of sections 290.500 to 290.530 shall be liable to the employee affected for the full amount of the wage rate and an additional amount equal to twice the unpaid wages as liquidated damages, less any amount actually paid to the employee by the employer and for costs and such reasonable attorney fees as may be allowed by the court or jury. The employee may bring any legal action necessary to collect the claim. Any agreement between the employee and the employer to work for less than the wage rate shall be no defense to the action. All actions for the collection of any deficiency in wages shall be commenced within three years of the accrual of the cause of action.
§ 290.527, RSMo