After his break up with "New Christine", Richard is spending a lot of time at her house. Ritchie tells his new teacher Mr. Harris that his parents are back together. Christine breaks this news to Richard. He suggests that they give their relationship another try.
Christine meets a handsome stranger and agrees to go out on a date with him.
Christine is surprised to learn that Ritchie is interested in attending church.
Barb and Pete decide they are going to get a divorce. Christine is excited to have a divorce buddy, but then Barb and Pete decide to get back together.
Christine has to serve lunch with Stan and Matthew's date won't go home.
Christine needs money for Ritchie's tuition, which she borrows from Richard. Richard then gets in trouble with the new Christine and ends up taking the money back. Barb comes up with a solution. She'll give Christine the money and be a partner in Christine's business.
Christine is hurt that Ritchie has so much more fun with his dad. She decides to put Richard in charge of Ritchie's mission assignment, but is upset when Ritchie's project doesn't turn out very well.
Christine and Barb struggle over how their new partnership in the gym will work, while Matthew helps Christine look for a nanny. Meanwhile, Richard takes new Christine on vacation to the same place he took old Christine on their honeymoon.
While at Ritchie's school Christine's car is hit by Marly's huge SUV. Marly wants to just let it go and each pay for their own car's damage. Christine agrees, but then finds out that Marly reported it to her insurance.
Christine and Richard meet with Mr. Harris who informs them that Ritchie is having trouble making friends. Richard insists that Ritchie joins the soccer team. Richard and Christine compete for Mr. Harris's attention at soccer practice. Ritchie makes friends, but they are all girls.
Christine convinces Matthew to let her go with him to a friend's party and then finds out that Matthew has a pretty ex-girlfriend. She tries get Matthew back together with his ex. Meanwhile, Richard takes Ritchie to his construction site, in an attempt to get Ritchie interested in his job as a contractor.
Richard is excited about his birthday. Christine resents the fact that Richard treats New Christine better than he treated her. Christine gives New Christine a good present idea for Richard, but then is upset that it was her idea and she's not getting credit for it.
Christine is having trouble relaxing and sleeping at night so her chiropractor suggests that she take sleeping pills. While on the pills she makes several phone calls that she can't remember. One of those calls is to her ex-boyfriend Burton who is having trouble getting over Christine.
Richard's brother Joe comes to town and comes over to Christine's when he can't sleep. He and Christine fall asleep watching a movie in her bedroom. She decides to stop things when he kisses her, but when she tries to tell him he admits that he's gay.
Christine misses voting and realizes that she's not involved in politics anymore. She decides to volunteer to set a better example for Ritchie. Meanwhile, Richard finds out that that Matthew and Barb made out before Barb got married.
Christine gets Mr. Harris and herself in trouble with the school when she accidentally sends a suggestive email to all the parents and Mr. Harris instead of to Barb as she intended.
Christine finds out that Richard is going to remodel Lindsay's bathroom and tries to talk him out of it. When he insists on taking the job, Christine comes over to check up on him and gets caught wearing Lindsay's coat on the nanny camera. Richard forgives Christine for costing him the job and tries to explain to Christine she'll feel better if she doesn't hold on to every little thing.
Christine volunteers to be the designated driver to prove that she can go to a wedding without drinking. The fact that she's sober doesn't help her to keep her mouth shut and she tells the bride that she slept with the groom. Meanwhile, Richard gets in trouble with New Christine when he tells her he's not interested in getting married again.
Ritchie goes on a school camping trip and Christine, Richard, Matthew and Barb stay at a nearby hotel in case he needs them. Matthew is uncomfortable around Barb and Christine and Richard rekindle their romance.
Christine fears that she may be pregnant after her night with Richard. She worries that one reckless evening may have ruined her chances of dating Mr. Harris who shows up to tell her he took a job at another school so they could give a relationship a try. When she discovers she isn't pregnant, both she and Richard, who has reconciled with New Christine, are relieved.