If Rule 56.32(a) did not apply to the rent and possession action, then the dismissal was improper. No other pertinent statute or rule requires counterclaims to be filed. Plaintiff did not contend in the trial court nor before the eastern district that Rule 41.01 was applicable in this matter, nor was it raised here until reference to that rule by the Court in questioning counsel during oral argument. Because of the importance of deciding whether Rule 55 applies in a rent and possession suit, and the possibility of manifest injustice should plaintiffs claim be improperly dismissed due to a neglect to raise the question, the applicability of Rule 41.01 is considered under the “plain error” provision of Rule 84.13(c).