Mo. Rev. Stat. § 506.130

The summons shall be signed by the clerk and dated the day it is issued, be under the seal of the court, contain the name of the court and the names of the parties, be directed to the defendant, state the name and address of the plaintiff's attorney, if any, otherwise the plaintiff's address, and the time within which the place where the defendant is required to appear and defend as provided by law, and shall notify him that in case of his failure to do so judgment by default will be rendered against him for the relief demanded in the petition.