In the fourth season, the normally boisterous Foster-Lambert household is shocked when Frank (Patrick Duffy) and Carol (Suzanne Somers) unload a little surprise on the family: She's pregnant! Carol and Frank are going to have a child of their own the first one who won't be identified with one half of the family or the other and the kids will have a new sibling. As each family member deals with the news in his or her own way (with reactions ranging from joy to jealousy), they ultimately pull together to prepare for this momentous event. While the clan prepares, Dana (Staci Keanan) adjusts to being Cody's (Sasha Mitchell) college classmate, Al (Christine Lakin) gets bad dating advice from Karen (Angela Watson), and J.T. (Brandon Call) gets the same from Mark (Christopher Castile) while real-life baseball legend Harmon Killebrew restores Brendan's (Josh Byrne) faith in heroes. And then all welcome Lilly Foster Lambert into the fold.