Mo. Rev. Stat. § 511.180: Bar to petition for review.

If the plaintiff shall, at any time after such final judgment, serve the defendant, within any of the United States or the territories thereof, with notice of the suit and a copy of the judgment thereon, and such defendant shall not, within one year after such service, bring his petition for review, the court, on proof of the service of such notice, shall make an order that the judgment stand absolute.