Twin sisters Liv and Maddie finally reunite when Liv returns to Wisconsin after spending the last four years starring 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. Meanwhile, Parker and Joey have to find tarantulas that escaped after Parker brought them home from school, before their parents find out.
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.
After Liv has a difficult time making friends at school, Maddie steps in to help. However, when Liv discovers she was set up and didn't make her new friend on her own, she ignores Maddie's warnings and instead befriends a girl known for causing trouble. Meanwhile, Joey is miserable at the new job he has accepted in order to pay back his parents for a hi-tech cell phone.
When Joey is too nervous to talk to a girl 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.
Liv convinces Joey to let her join his Brain Olympics team, even though he doesn't think she's smart enough - and she's set on proving him wrong.
Karen throws Maddie a curveball about the day she was born, and she and Liv realize planning their sweet 16 party together may be more complicated than expected.
Liv sings a duet with a 9-year-old wannabe singer at the local holiday show. Meanwhile, Pete and Maddie decorate the town's Christmas tree; and Parker interferes with Joey's holiday get-rich-quick scheme.
When Liv is up for a big sci-fi movie role and Maddie has to take her driver's test, the girls switch places for the day to help each other out.
Maddie and Pete sign up to play in a basketball tournament.
The kids mistakenly believe that 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 is anxiously awaiting the arrival of a letter from the Junior Olympics that will tell her if she's been invited to try out for the basketball team.
Maddie is jealous when Liv's best friend from Hollywood, South, comes to visit and flirts with Diggie.
Liv's new music team takes a huge step in the wrong direction, causing her latest single to be a viral hit for all the wrong reasons.
To prove to the skeptics that she is meant to star in "Space Warewolves," Liv agrees to do all her own stunts, not realizing exactly how complicated they are.