In the summer of 1958, Greaser (subculture) Danny Zuko and sweet Australian girl Sandy Olsson meet at the beach and fall in love. When the summer comes to an end, Sandy, whose family is returning to Australia, worries that they might never meet again, but Danny tells her that their love is "only the beginning." At the beginning of the new school year at Rydell High School ("Grease"), Danny reunites with his fellow gang members, the T-Birds, of whom his best friend Kenickie, along with Doody, Sonny, and Putzie are members. Meanwhile, unbeknownst to Danny, Sandy arrives at school, with her family's plans having changed, with her new friend Frenchy, a member of the Pink Ladies. Other Pink Ladies Rizzo, Marty, and Jan also arrive, excited to be seniors, as does Patty Simcox, a high-achieving cheerleader.
It is 1961, two years after the original ''Grease (film)'' ended. The first day of school has arrived ("Alma Mater" from Grease (musical)) as Principal McGee and her secretary Blanche react in horror as the students, among them the new street gang and Pink Ladies, arrive at high school ("Back to School Again"). The Pink Ladies are now led by Stephanie Zinone, who feels she has "outgrown" her relationship with her ex-boyfriend Johnny Nogerelli, the arrogant and rather immature new leader of the T-Birds.
In 1954, before rock ‘n’ roll ruled, before the T-Birds were the coolest in the school, four fed-up outcasts dare to have fun on their own terms, sparking a moral panic that will change Rydell High forever.