The action may be commenced by any lienholder who has filed a lien statement for record and served a copy thereof on the owner pursuant to section 514.08, and all other such lienholders shall be made defendants therein. The summons shall state that the complaint has been filed with the court administrator and shall be of no effect unless such complaint be in fact so filed. It shall contain a notice that the action is brought to foreclose a lien, giving the amount thereof, and a brief description of the premises affected, and of the improvement out of which the lien arose, and shall require each defendant to file an answer to the complaint with the court administrator within 20 days after service on the defendant. Such answer, in addition to all other matters proper to be pleaded, shall set up any lien claimed by the defendant, and demand the enforcement thereof. No copies of such complaint or answer need be served on any party, upon demand or otherwise, and all averments of the answer shall be taken as denied without further pleading.