Twin sisters Liv and Maddie finally reunite when Liv returns home to Wisconsin after starring for four years in a hit musical television show in Hollywood. The Rooney sisters quickly realize their polar opposite personalities put their unbreakable twin bond to the test. While their parents play referee between Liv, a cool, confident, social butterfly who loves to sing, and Maddie, a smart, athletic, high school basketball star who opts for high tops over high heels, brothers Joey and Parker seize the opportunity to capitalize on the chaos and get away with as much as they can.

Maddie is named captain of the girls' basketball team just as the school principal announces he is cutting funding for the program. Determined to change his mind, Maddie voices her concern to the principal, only to realize her team has abandoned her. Frustrated with her lack of leadership skills, Maddie turns to Liv to help her earn the team's respect. Meanwhile, Parker and Joey are challenged trying to find a bevy of tarantulas that escaped after Parker brought them home from school unbeknownst to their mom.

After Liv realizes just how much Parker has grown up while she was away, she volunteers to supervise his sleepover in hopes of reconnecting with him. But when all her activities backfire and start to embarrass Parker in front of his friends, Liv has to up her game in order to impress her little brother. Meanwhile, Maddie and Willow work on a school project, and Joey and Pete go on a road trip to the Pastrami Palace that leads to a wild night of fun.

When Joey is too nervous to talk to the new girl who he likes, Maddie decides the best place for him to practice talking to girls is at the high school dance–when everyone is in costume. Meanwhile, Parker booby-traps the house to protect one of the family’s most prized Halloween decorations from being stolen.

Liv wants to back out of being a celebrity judge at a skateboarding competition after her boyfriend, a skateboarding pro in town for the competition, breaks up with her via text. Meanwhile, Joey and Parker are ecstatic when they meet a masked skateboarding pro who is famous for his massive wipeouts.

When Liv decides to volunteer at the senior center where Maddie works, chaos ensues and the seniors get the girls involved in a rowdy game of dodge ball to claim their turf.

Ridgewood High is hosting the annual "Brain Olympics", and Joey is intent on forming a team in hopes of winning. Liv, in an effort to shed part of her girly image, convinces Joey to let her join the team. In competition, each team has to build a Rube Goldberg machine, but when Joey thinks she is not clever enough, Liv decides to build her own. Meanwhile, Maddie holds a yard sale to raise funds for the French Club's trip to Montreal, and a priceless childhood memory accidentally gets sold.

Liv and Maddie try to plan their sweet 16 party but complications arise.

The annual Stevens Point Holiday Spectacular is coming up, and Liv is asked to host the televised event. When Liv discovers the little girl she's asked to perform with shares the same strong desire for the spotlight, trouble ensues. Additionally, Pete and Maddie are in charge of decorating the city's Christmas tree, but the power goes out amid Liv's performance. Meanwhile, Parker swindles money from Joey while dressed as Santa and an elf in order to purchase an expensive present he suspects no one will gift him.

When Maddie fails her driving test and Liv needs help trying to get a part in a sci-fi play, they decide to switch so Liv takes Maddie's driving test and Maddie auditions for Liv. But when Maddie accidentally yells, "Bam! What!?" Joey and Parker realize it's her and not really Liv, and Liv wrecks the car during Maddie's driving test.

Maddie and Pete sign up in a basketball Tournament.

When the kids overhear their parents' conversation, they mistakenly believe they are moving.

Maddie and Willow are excited to try out for the school's varsity softball team, but Maddie, the catcher, realizes that Willow, the pitcher, is in a slump because she can't stop thinking about Joey.

Maddie and Karen take part in a historical society's annual mother-daughter weekend of pioneer living.

In an effort to help Maddie bring out her “girly side,” Liv gives her a pair of the most comfortable high heels ever made.

Liv is told that the coveted role of Tristan in “Space Werewolves” has been narrowed down to herself and two other famous actors.

Maddie anxiously waits for a letter from the Junior Olympics to arrive to find out if she is invited to try out for the basketball team.

Maddie gets jealous when Liv's best friend from Hollywood visits and flirts with Diggie.

Liv's new music team makes a big mistake that causes her latest single to become a viral hit for all the wrong reasons.

To prove to the skeptics that she is meant to star in “Space Werewolves,” Liv agrees to do all her own stunts, not realizing exactly how complicated they are. Maddie tears her ACL and needs surgery, therefore not being able to play in the championship or go to the Junior Olympics.