The Bradfords bid adieu to the seventies by ushering in even more changes to the clan dynamic in Season Four. First up, minor league ball player Merle "the Pearl" Stockwell (Brian Patrick Clarke) sweeps Susan (Susan Richardson) off her feet. An engagement soon follows, but there's one problem -- David (Grant Goodeve) has already set THEIR date for HIS wedding while Nancy (Dianne Kay) has a singing telegram gig that day And first comes marriage, then comes Mary (Lani O'Grady) finding a positive home pregnancy test! Meanwhile, Joanie (Laurie Walters) and Tom (Dick Van Patten) become competing journalists, Nicholas (Adam Rich) curses the family by breaking a chain letter, and Tommy (Willie Aames) runs for Prom Queen! On the more tender side, Abby (Betty Buckley) comes to grips with the memories of her deceased husband, while Tom is forced into a reunion with the father he has not seen in forty years -- and he's about to turn fifty!