The Case of the Moth-Eaten Mink - S1-E13
Plot hole: Perry Mason and Della Street are having dinner at a restaurant owned by Morey Allen. When waitress Dixie Dayton sees a diner who has been stalking her, she flees and is hit by a car. The next morning, Perry's incoming mail includes a retainer from Allen. His letter and check would not have arrived until the following day, at the earliest.
