In the second-season premiere, after Mary Richards produces a ""What's Your Sexual IQ?"" documentary for the Six O'Clock News, Rhoda confesses to failing and Phyllis says that young Bess watched it. Phyllis calls on Mary to teach Bess the facts of life, but it turns out that Bess already had learned it from her friends. Meanwhile, the WJM-TV newsroom is shelled with phone calls responding to the documentary. According to Mary, more people are appalled by it than anything else.

When Ida, Rhoda's mother, visits, she sees how well Phyllis and Bess get on, and how closely Mary appears to her mother when they chat on the telephone, that she tries to be Rhoda's ""friend"".

Mary agrees to babysit Bess for the weekend, but then a former boyfriend, in town for a few days, asks her out. When she can't find a babysitter for Bess on such short notice, she ends up asking Lou.

Bess gets top marks for a report she wrote for school, and Phyllis pressures her to write a book based on it, calling on Mary for help.

Bess's 15-year-old boyfriend falls in love with Mary and begins to surprise her with visits to her apartment and her work.

Mary dates a man with whom she has nothing in common and becomes concerned that their relationship is superficial.

Lou wants a smaller place and moves in to Rhoda's old apartment but can't help interfering in Mary's private life.

Phyllis and Lars have a dispute and she finds her credit cards cut off. She looks for a job but finds that she has no relevant skills.