Best friends Ashley Sanchez (Ash) and Ashlee Taylor (Lee) agree that being a sister can be tough. What they don't agree on is which of them has it tougher. When they both argue that their situation is worse, the two girls decide to switch places for a day. Ash can't wait to spend time with Lee's cool older sister, Mallory. Lee is excited to bond with Ash's adorable baby brother, Sam. But when the sibling swap doesn't go as expected, will Ash and Lee still wish to trade places?