After waiting to consummate her relationship with Mr. Harris, Christine is finally ready - until Barb gives her reason to worry. Meanwhile, Matthew rethinks med school after discovering that his assigned cadaver is a former neighbor.
Christine considers having plastic surgery after a pretty young waitress flirts with Mr. Harris. Matthew decides he wants to be a therapist and when new Christine doesn't call him back, Richard proposes to her, but is relieved when she says no.
Christine is shocked when a new dad at Ritchie's school calls her a "meanie mom" for being judgmental and standoffish, and dumps her for Marly and Lindsay.
Christine promises to accompany Mr. Harris to an important event, but leaves him hanging when Ritchie's soccer game runs long. She sends Barb to deliver a message to Mr. Harris that she's going to be late, but Barb and Mr. Harris don't get along. After the dinner, Mr. Harris breaks up with Christine because she's too busy for him.
Christine attempts to get over her breakup with Mr. Harris and goes rock climbing at a birthday party she's taken Richie to. Meanwhile, Matthew goes to therapy and learns that his intimacy issues are not due to his dysfunctional relationship with his mother, but from his co-dependency on his sister.
When Christine learns that Richard and New Christine bought the house she had always dreamed of, she attempts to feel genuinely happy for them.
New Christine sets Christine up on a blind date. Christine is shocked when she meets him--he's half her age. However, even after the evening is a disaster, Christine still agrees to another set-up.
When Christine and Barb find some pot in a purse in lost and found, Christine tries to convince Barb that she is not square and goes to find more marijuana.
Barb and Matthew, who are still determining whether to be a couple after an intimate night together, pretend to be inseparable after Christine tries to keep them apart.
When Christine's gynecologist suggests that her flu symptoms may be a sign of perimenopause, she decides to take her hormones into her own hands.