Mo. Rev. Stat. § 509.070: Two claims may be joined in a single action, when — court shall grant relief, when.

Whenever a claim is one heretofore cognizable only after another claim has been prosecuted to a conclusion, the two claims may be joined in a single action; but the court shall grant relief in that action only in accordance with the relative substantive rights of the parties. In particular, a plaintiff may state a claim for money and a claim to have set aside a conveyance fraudulent as to him, without first having obtained a judgment establishing the claim for money; a plaintiff may state his original claim against the defendant and also in either the original or an amended petition or a reply, a claim for having any release, composition, settlement, or discharge of the original claim set aside as fraudulent or otherwise wrongfully procured.