You will need to file your answer to the complaint (complaint is the lawsuit attached to the summons) with the court and mail a copy of your answer with an attached proof of service to the attorney.You will need the case number in order to file the answer and proof of service with the court.  The summons probably does not have a case number because the copy you received may have been sent to you before the original was filed with the court. You should call the attorney to get the case number.  If for some reason that is not feasible, the name of the court where the summons and complaint were to be filed should appear on the documents.  You could go to that court and look for your name under defendants in the plaintiff/defendant index in the court's computer and obtain the case number.  Once you have the case number, you could ask the court clerk to see the file.  You won't be able to remove the file from the court, but can request a copy if you want; however, at this point in the case, the only item in the file should be the summons and complaint.