Troy, Gabriella, Chad, and Taylor spend their summer vacation working at a country club founded by Ryan and Sharpay's family, but the club's annual talent show is threatened when Sharpay dumps Ryan as a singing partner and woos Troy into joining her onstage, which upsets Gabriella.

Younger sister Hayley Wheaton (Danielle Harris) wishes to switch places with her popular older sister Alexia (Katherine Heigl) and the two bickering siblings awaken to find the wish has come true.