Mitchie Torres, Demi Lovato and her mother Connie Torres, Maria Canals-Barrera, return to Camp Rock for another summer. They notice a new camp across from them, Camp Star, and realize Camp Rock has fewer campers this season. After Opening Jam, the camp's meet-and-greet, Camp Star sends snacks to Camp Rock and invites them to a bonfire that night. Brown Cesario, Camp Rock's director, is hesitant to attend, since Camp Star was founded by Axel Turner, whom Cesario kicked out of his band years ago. Daniel Fathers waits on the sidelines, while Daniel Kash as Axel Turner looms as part of the new rival.
Most of Camp Rock attend at Mitchie's behest, and they soon realize the bonfire is a costly, elaborate performance designed to lure their campers and counselors to switch to Camp Star. A few campers join, including Tess Tyler, Meaghan Jette Martin, and several counselors switch sides. With a lean staff, Brown announces the closure of Camp Rock, but Mitchie and her friends persuade him to keep it open by taking on counselor roles themselves.
During the performance, Axel Turner spends huge sums to ensure Camp Star's votes, and Dana Turner, Chloe Bridges, daughter of Axel, begins to bond with Nate Gray, Nick Jonas. Dana is later dismayed by Nate's laid-back attitude, even as their bond grows.
Mitchie and her friends struggle to settle into their new counselor duties. They revisit Camp Star, which is shown to focus almost exclusively on music, with little room for other activities. Axel Turner suggests broadcasting a televised competition between the camps to boost interest, and Mitchie reluctantly agrees after pressure from her friends. Brown reacts with anger, and Mitchie overhears him telling Connie that if Camp Rock loses, the camp could be closed for good.
Shane Gray, Joe Jonas, returns to Camp Rock to spend time with Mitchie, which heightens the tension as Mitchie pushes toward victory. The group organizes a playful water-balloon fight to lift spirits and reconnect with the campers, but Mitchie sulks at the disruption. The next day, she discovers the group rehearsing for the competition led by Shane, and the two reconcile, renewing their connection.
Meanwhile, Nate slips into Camp Star to tell Dana how he feels, and is caught by Axel Turner, a moment that underscores the fragile lines between loyalty and romance across the rival camps.
At the competition, Brown learns that Axel has spent vast sums to secure Camp Star's edge. Camp Rock performs with a montage of their summer activities, but Camp Star wins in a controversial finish. Mitchie apologizes to Shane for neglecting him, and they share a kiss, signaling a renewed bond.
At the final Camp Rock bonfire of the season, many Camp Star members, including Tess Tyler and Dana Turner, opt to join Camp Rock, drawn by its culture and community. Their switch ensures Camp Rock has enough campers to return for another summer, closing the chapter on this summer’s rivalry with a hopeful note for the future.
