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.

Liv has a difficult time making friends at school so Maddie steps in to help.

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.