Following the events of the first film, a new term begins at St Trinian's with Annabelle Fritton appointed as the new Head Girl. Meanwhile, new student Roxy is introduced to the various school cliques—the Chavs/Rude Girls, the Emos, the Posh Totties and the Geeks. Along with two new groups, the Flammables and the Ecos—with Roxy choosing not to join any of them. Later, the girls catch Celia, a member of the eco sect, retrieving an old ring from the school's Fritton Archives. Celia explains that an unknown man telephoned her to retrieve it for him in exchange for £20,000. Seeking to get more, Annabelle demands £100,000 from the man when he calls back, only for him to refuse and threaten the girls for their greed. When the school's power is cut, the girls ask their headmistress, Camilla Fritton, Annabelle's aunt, about why the ring might be so valuable. Camilla recognizes the ring as one of two created by a pirate ancestor of hers and Annabelle's in 1589, which, when united, reveal the path to a buried treasure hidden somewhere in the world. Shortly after this discovery, the school is attacked by masked men led by Sir Piers Pomfrey—a man of impeccable reputation and a descendant of the man robbed by Camilla's pirate ancestor—who steals the ring in a bid to find the treasure himself. Seeking to stop him, the girls search for the second ring and find a clue left by another ancestor who located the second ring and left it in the archives. After a difficult time deciphering a clue they left, the girls find it to be hidden within a boys' school, leaving a group to infiltrate it in disguise and recover it. Seeking to recover the first ring, the girls learn that Piers is the leader of a secret society known as AD1, a
masculinist brotherhood, and that Camilla's old flame and former head of education, Geoffrey Thwaites, knows about him and the society. After tracking him down at a pub, Camilla convinces him to help them—whereupon she puts him through a course to help him overcome his need for
drink—and assigns him to work undercover at AD1's hideout, with Annabelle calling in the former head girl Kelly, now an
M.I.7 agent, to assist in the recovery of the ring. Despite the girls not finding it in the vault, Geoffrey spots it being worn by Piers and manages to steal it from him, returning it to St Trinian's. Finding that the two rings bear longitude and latitude coordinates respectively on them, the girls find that the treasure is buried under the
Globe Theatre. After organising a flash mob to keep AD1 from pursuing them—after Piers learns they recovered the first ring—Camilla, Geoffrey, the school's bursar, Annabelle and a small group of the girls make it to the theatre, and while the girls head underneath the building, Camilla and Geoffrey pose as actors they knocked out to avoid raising any alarm. Although the girls make it to the treasure's location within a secret room, they discover a chest within containing nothing more than a note from Pirate Fritton, who gave up being a pirate to write plays under the name of
William Shakespeare, and that the treasure was the final play he wrote intended to reveal that "he" was a woman. Piers, managing to track them down, holds them at gunpoint and steals the play's script from them, revealing that his ancestors knew Captain Fritton was a woman (and Shakespeare) and that he had always intended to find the play and destroy it so that nobody else would find out. The girls watch as he flees the scene on his private boat. Seeking to stop him, the girls take control of the reconstruction of the
Golden Hind and sail it down the
Thames, whereupon they attack Piers' boat, with Camilla recovering the play's script from him. The girls soon return to St Trinian's for a wild party to celebrate their success, while Piers is exposed for being a sexist after AD1 is revealed to the media. ==Cast==