A Night Not to Remember is the premiere episode of Season 7 of Three's Company, and the 129th overall episode of the series. Written by George Burditt and Budd Grossman and directed by Dave Powers, it first aired 28 September 1982 on ABC.
Janet has to go out with Mr. Hagen, an important man from the flower shop's home office. As Mr. Hagen has a reputation for being lecherous, Janet convinces Jack to accompany her for protection, even though Jack has a bad cold. Jack proceeds to get thoroughly drunk on exotic drinks and, later that night, unknowingly falls asleep on Janet's bed. When she tries to get him out of her bed, Jack accidentally breaks a vase given to Janet by her grandmother. Jack again falls asleep on her bed, and Janet falls asleep on the same bed.
In the morning, Jack is appalled to find himself in bed with Janet. He remembers nothing about the previous night, so when Janet is angry with him about the vase, he assumes she's mad because he broke the trio's rule about fooling around with a roommate. Jack begins to pack to move out, but Janet talks to him and clears up the misunderstanding, and the trio is happy once again.