Mary returns with a new format, a kind of show within a show. She plays Mary McKinnon, whose TV variety show provides a vehicle for weekly guests, and a frame for backstage comedy. On the curtain raiser, Mary's attempts to land Lucille Ball on her program land them both on ""The Mike Douglas Show,"" both in a state of advanced inebriation. Lucy and Mary sing ""Girl Friends of the Whirling Dervish.""-TV Guide March 3-9, 1979
Mary tries to cope with the eccentricities of her two guests: militant crusader Beatrice Arthur; and washed-up vaudevillian Benny Baxter(played by Howard Morris), who'll do anything for a cheap laugh.-TV Guide March 10-16, 1979
Mary's guests are Bonnie Franklin and Henny Youngman-but the show may not go on if Mary and Bonnie can't extricate themselves from a confusing session of night court. Meanwhile, Henny gets to regale a German impresario with a simultaneously translated monologue. Musical Highlights: ""I Won't Dance""...Bonnie and Tony Stevens; Disco Mother Goose medley...Bonnie and Mary-TV Guide March 17-23, 1979
Guest Dick Van Dyke haggles with writers over sketches while Mary worries about a brush fire that's edging dangerously close to her house. In fantasy bits, Dick and Mary reprise their Rob and Laura Petrie roles playing the couple in their later years; and do a ""walking"" medley.-TV Guide March 24-30, 1979
Mary is frankly in awe of guest star Gene Kelly, fearful that she won't be able to keep in step with him. Songs include a Gene Kelly medley (Mary) and ""Ballin' the Jack""(Gene, Mary).-TV Guide March 30-April 6, 1979
Mary welcomes Johnny Mathis and an uninvited guest-her goddaughter Mary Ellen(Claudia Lonow), a stagestruck 16-year-old who hopes to make it big in Hollywood(with a little help from Mary). Musical Highlights: ""Last Dance""...Johnny; ""There's a Place for Us""...Johnny and Mary.-TV Guide April 7-13, 1979
Housing problems beset Mary's circle: the house that guest Ken Howard rents at Mary's suggestion makes the House of Usher seem sturdy by comparison; and Iris leaves Mary's employ to pursue what she imagines to be a promising career selling real estate. Musical Highlights: ""All I Need is the Girl""...Ken; ""Sweet Georgia Brown""...Mary and dancers.-TV Guide April 14-20, 1979
Guest Hal Linden acts as peacemaker when Mary has a falling out with producer Harry(Michael Lombard) over a misquote in a gossip column. Musical Highlights: ""All by Myself""...Hal; ""Johnny One Note""...Hal and Mary.-TV Guide April 21-27, 1979
Mary and guest Linda Lavin are distracted during their performance by a televised awards ceremony-on which they are competing in the same category. Also: comic Morty Gunty does a routine. Musical Highlights: ""Magic to Do""...Mary; ""Someone to Watch Over Me""...Linda; ""At the Moving Picture Ball""...Linda and Mary.-TV Guide April 28-May 4, 1979
Mary becomes exasperated with guest Nancy Walker, whose preoccupation with union business is disrupting rehearsals. Also: Kenneth(Michael Keaton) escorts a star-struck ingenue to Mary's house, where a bedridden Ruby is recuperating from an unknown ailment. Musical Highlights: ""Friendship"" medley...Nancy and Mary; Flamenco dance...Nancy and dancers.-TV Guide May 5-11, 1979