Andi Mack has been raised to live on the safe side, sheltered by overprotective parents. But on the eve of her 13th birthday, Andi's free-spirited older sister Bex returns home with a revelation that changes everything, sending Andi on an uncharted course of self-discovery. Thankfully, she's anchored by her loyal best friends, Cyrus and Buffy, who are also figuring out their places in the world. Along the way, Andi learns that sometimes the unexpected is what makes life great.