Wings - Season 6 - Eps 2: Twisted Sister
The arrival of Helen's elder sister Casey to Nantucket sidetracks Joe's plan to give Helen an engagement ring. What was originally planned to be an evening for two at Lexington's becomes a party of four, with Casey along to catch up with Helen and Brian along to occupy Casey. Then, before Joe can give Helen his ring, Casey gives Helen an even bigger ring as a gift, and Joe's angry frustration brings the night to a halt. He apologizes later that night and gives her the ring, but once again Casey drops in to spoil things. Helen finally stands up to Casey, who then reveals that her husband has left her, and she has no where to go. So Helen invites her to stay with her for as long as she wants.
About Wings

Title: Wings
First Air Date: 1990-04-19
Last Air Date: 1997-05-21
Status: Ended
Rating: 6.9/10 (from 125 votes)
Language: EN
Seasons: 8
Total Episodes: 172
Network: NBC
Genres: Comedy, Drama
Production Companies: Paramount Television, Grub Street Productions
Synopsis
Brothers Brian and Joe Hackett attempt to run an airline on the New England island of Nantucket while surrounded by their various wacky friends and employees.
Cast

Tim Daly
Joe Hackett

Steven Weber
Brian Hackett

Crystal Bernard
Helen Chapel

David Schramm
Roy Biggins

Rebecca Schull
Fay Cochran

Tony Shalhoub
Antonio Scarpacci

Amy Yasbeck
Casey Davenport