Love that Baby was a popular television series that was the start of Mary Dahl's career, and also its demise.
The show centered on the mischievous Baby-Doll, starring Mary Dahl, who stole the hearts of audiences everywhere. Dahl started out when she was ten, and due to a rare condition called hypoplasia (which prevented growth and puberty), she looked the same ten years later at age 20.
Other cast members included Tod Baker as Baby's dad, June Winthrop as Baby's mom, Tammy Vance as Baby's teenage sister, Suzy, and Brian Daly as Baby's older brother, Tippy. However behind the scenes, Tod admitted he did not like working with Mary, whom he regarded as ratings hungry and a selfish brat.
During the show's tenth year on TV (the final season), ratings started to drop, so in an attempt to boost them, studio executives added a new character to the show: Baby's cousin, Spunky, who became a popular character and managed to upstage Mary during the birthday episode of the show. While this provided "Love That Baby" with the ratings boost it needed, it also made Mary very angry at being upstaged, and she demanded that Spunky be removed and she be given back the spotlight. When the studio refused to meet her demands, she walked off the show and tried pursuing a career as a dramatic actress. Since the studio couldn't do the show without its titular star, they had to cancel it, putting Mary's costars out of work.
After Dahl's stint as a serious actress ultimately failed, she tried restarting her show, but no network wanted to pick it up, and only Daly was implied to have been sympathetic to the state of Dahl's career. As Batman pointed out, what made Mary Dahl famous ultimately turned her into a recluse, ironically.
Another ten years later, Dahl lost her mind: she abducted her former co-stars and held them prisoner so she could live out her dream, living with her "family" forever. All her family, that is, except Cousin Spunky. She recreated the birthday episode with an explosive twist. After the Spunky whom she captured turned out to be Robin in disguise, who brought the cast members to safety while Batman entered to take care of Dahl.