Amber fails to defend Jonah Beck when her friends mock his Space Otters team, causing Jonah to turn to Andi. Meanwhile, Andi is convinced Bex and Bowie are destined to be together.

Bex encourages Andi to stand up for herself and challenge an unreasonable new dress code, so Andi, Buffy and Cyrus practice their newfound empowerment and start a protest.

Andi and Bex struggle to get comfortable with their new living arrangement; Cyrus thinks Iris has dumped him so he enlists Buffy to fill in as his date.

When Jonah asks Andi for help picking out a birthday gift for his girlfriend, Amber, Andi enlists the help of Bex.

Andi yearns for time to herself after catching someone snooping through her laptop; Cyrus is challenged by a text from Jonah Beck and enlists Buffy's help.

Celia forces Andi to go to school instead of going on a fun adventure; Andi learns something important about Jonah and Amber.

Buffy and Cyrus convince Andi to tell Jonah the truth about Amber, but it leads to Andi feeling humiliated. Bex lets Andi stay home from school and they get an unexpected visitor.

Ham works to convince Bex to contact Bowie and tell him the truth; Andi's frustration boils over when she discovers that Buffy has secretly been confiding in Bex instead of her. Meanwhile, Cyrus double-dates with Jonah Beck, Amber and her friend Iris.

Ham takes Celia on a weekend getaway, so Bex emboldens Andi to host her first-ever dance party at the house – and then Amber shows up, dampening Andi's big night. Buffy meets Marty, a guy from the school track team.

Against Celia's wishes, Bex convinces Andi to stay up late to watch a scary movie; and when Andi falls asleep in class the next day, she receives detention and then misses the Space Otters game. Meanwhile, Buffy joins the track team and is determined to win.

Andi decides to keep the news about Bex a secret.

Andi's world turns upside down when her older sister, Bex, returns home on her 13th birthday and / Andi Mack has been raised to live on the safe side, but on her 13th birthday a revelation jumpstarts her path to self-discovery. At every twist and turn, she's anchored by her loving albeit complicated family and her loyal best friends, Cyrus and Buffy. Andi's life is further complicated by the arrival of her older sister, Bex, who has a secret that changes both their lives forever. As she determines where she fits in, and the many amazing ways she can live her life, she quickly learns that sometimes the unexpected is what truly makes life great.