Montana Title 25. Civil Procedure § 25-31-406. Time for answer or appearance

(1) if an order of arrest is endorsed upon the summons, immediately;

(2) in all other cases, the summons must provide that the defendant shall answer in writing, file the answer, and serve a copy upon the plaintiff or the plaintiff's attorney within 20 days after service of the summons, exclusive of the day of service, and in case of the defendant's failure to appear or answer, judgment will be taken against the defendant by default for the relief demanded in the complaint.