They say the third time’s the charm and reformed party girl Kate is hoping that’s true when she becomes Pete's third wife. She fell into his arms (literally) at a karaoke bar and a year later, Kate’s got an insta-family complete with three stepchildren and two ex-wives. Diane is ex-wife number one, an intense, over-achieving doctor and the mother of twin teenagers Hillary and Warren. Diane is quick to convey her withering disapproval of Kate’s barely tapped maternal instinct. Ex-wife number two, Jackie, is mother to adopted son Bert, and can pull Pete’s strings with her special blend of neurotic, new-ageyness. Juggling all this baggage is uncharted territory for Kate, who finds support with her best friend Meg, a party-hearty singleton and the only woman Kate knows who has less experience with kids than she does.
Kate is in uncharted territory and finds support from her best friend Meg a party-hearty singleton and the only woman Kate knows who has less experience with kids than she has.
When Kate asks Pete for more responsibility, he entrusts her to put Bert to bed and help him coach Bert's soccer team. Before soccer practice, Bert drinks Kate's coffee and becomes a wild man on the field before crashing. Meanwhile, Warren and Hillary spill salsa on Diane's immaculate white couch and try to hide it from her.
When Hillary is grounded after being caught lying in order to hang out with a boy, Diane and Pete decide they must snoop in her room and on her Facebook page to find out more about the young man, while Kate tries a different tactic – to be Hillary’s friend. Meanwhile, Albert gets a little too invested in Jackie’s latest career venture.
When Meg stays with Kate and Pete after a break-up, Kate is torn between her friendship and obligations as a wife and step-mom. Meg’s criticism of Kate’s life causes the long time friends to have a falling out and it’s up to Pete to help them work it out. Meanwhile, Warren struggles with the pressures of figuring out his future but gets a glimpse of his true talent when he helps Bert with a Lego project.
Between everyone’s crazy schedules and activities, Pete and Kate are having a tough time finding any alone time, so at Diane’s 80s-themed school fundraiser event, they attempt a risqué romantic romp inside the janitor’s closet. Meanwhile, back at home, the kids help Jackie with her online dating profile, but Bert is less than enthusiastic.
Halloween is Jackie and Bert’s most favorite holiday, but when Jackie’s homemade Iron Man costume doesn’t turn out the way Bert had intended, Kate swoops in and hijacks the holiday. Meanwhile, Pete suspects a masked trick-or-treater as the same teenage misfit who egged the house and mooned him last year, so he holds the kid hostage trying to force a confession.
When Kate and Pete host a party, Jackie crashes and hooks up with Pete’s co-worker Sad Steve, much to Pete’s discomfort. However, when Sad Steve decides to pursue a relationship with Jackie, both Kate and Pete jump on the bandwagon to give young love a boost. Meanwhile, Hillary helps Warren and Bert put together a Gum Show live stream, and Diane faces off with Meg after she posts an unflattering picture of her on Instagram.
When the Harrison household is infected with lice, Diane tries to take charge leaving Kate feeling bulldozed. Jackie and Kate work together to try to prove a point to Diane, but their plan back fires and the lice problem worsens. Meanwhile, Pete plays mediator between Warren and Bert, who are fighting over custody of a teddy bear.
When Kate tries to play matchmaker with Diane and another parent on a field trip, she soon learns that Diane is more challenging to set up than she originally thought. Meanwhile, Jackie decides to nurse Pete back to health and Hillary helps Bert get on his teacher's good side.
Pete, Kate, Diane and Jackie wake up Christmas morning hung-over and the house in complete disaster. They try to piece together the events of last night’s Christmas Eve festivities while also trying to save Christmas for the kids.
When Kate attempts to break Pete's birthday curse and help him have a fun birthday, the curse proves to be more powerful than she anticipates. Meanwhile, Diane and Jackie shop together for Pete's birthday gift and the kids are at home with lobsters that refuse to be a main course.
When Hillary and Warren misbehave on Kate’s watch, Kate turns to Diane for help in disciplining them, and Pete and Jackie try to set a good example by taking Bert on a nice outing together, but it proves to be harder than they anticipated.
When Bert loses a tooth and Pete misplaces it, his solution causes big problems with Jackie. Meanwhile, Kate channels her maternal nature and advises Warren during his first study date, and Diane helps Hillary host her first high school sleepover, which leaves Hillary feeling embarrassed.
Kate decides she wants in on Jackie’s latest business venture of catering and delivering healthy kid lunches, but when they disagree on quality versus quantity, things get very messy. Elsewhere, Pete takes Warren and Bert to karate lessons in hopes of teaching them discipline and integrity, however, the instructor Sensei Rick has a more combative approach.
When Bert successfully reads a hundred books, Pete and Kate have to throw him the birthday party of his dreams - complete with a fire eater on stilts, professional dancers and a special visitor. Kate uses the party planning as an excuse to get in with the soccer moms that shun her at all the games, and Diane refuses to admit fault while doing some creative driving with Pete. Meanwhile, Warren starts a bromance with the guy Hillary has her eye on.
When Kate finds Pete’s old wedding videos with Diane and Jackie, she realizes she robbed herself of that special memory by eloping and is now determined to have a redo and plans her dream wedding. Meanwhile, Diane decides to take her relationship with Russ Bradley Morrison public and Jackie struggles to tell Bert she’s dating Sad Steve.
Wedding planning continues as Kate will not be fazed by all the stress and chaos around her, which is only amplified by the arrival of her mother and Pete's parents. However, things come to a screeching halt when the family gets some bad news.
When Pete swaps out his chili for Kate’s at the school frontier fundraiser, Diane confronts him and he concocts a story about how he and Kate are going to couples counseling. Meanwhile, Meg relaxes at the Harrison’s house and becomes an object of fascination for Warren and Hillary.
After Kate saves Diane from choking, she takes over the PTA and finds it harder to navigate than she thought. When faced with blackmail, she turns to Diane to make sure “it’s handled.” Meanwhile, Pete and Jackie confront their former neighbors after they forbid their son to go to the school dance with Hillary, and Warren tries to get Vanessa Hudgens to be his date.
Concerned about Warren’s social life, Kate encourages him to make new friends and get involved in clubs or sports, however, it backfires and now she might have made things worse for him. Elsewhere, Hillary struggles with her art assignment and looks to Jackie for some creative guidance, and Pete teaches Bert the value of money.
Kate begrudgingly agrees to accompany Jackie to her high school reunion, not fully realizing all that it entails. Meanwhile, Pete and Diane take Hillary and Warren to visit a college campus and Bert is left in the care of Meg and Tevin.