Build a movie plot around this: How do the girls infiltrate the other school? disguising themselves as boys
The answer to this question is:
One night, an unknown man telephones St. Trinian's and bribes a girl, Celia, to find an old ring in the school library. She is caught by the other girls, and forced to explain that the man offered her 20,000 for the ring. Annabelle, the new head girl of St. Trinian's, bartered for 100,000 from the man when he called back, but he refused and then proceeded to threaten them. Afterwards, the girls ask the headmistress, Camilla Fritton, about why the ring might be so valuable. She tells them a story about Pirate Fritton, her ancestor, who supposedly hid a great treasure somewhere in the world. He had two rings made, which when fitted together would reveal the location of the treasure.The man on the telephone who wanted the ring is Sir Piers Pomfrey, a member of a secret society, and descendant of a man robbed by Pirate Fritton in 1589. Sir Piers manages to steal the ring from headmistress Camilla. The girls decide to search for the second ring, and find a clue left by another ancestor of the Frittons, who found the first ring (left in the library) and believed he knew where to look for the second. After a difficult deciphering of the clue, a midnight hunt in a graveyard, dealing with demonic possession, and disguising themselves as boys to infiltrate another school, the girls find the elusive second ring at last.Now, all that is left is to steal back the ring that Sir Piers Pomphrey took.They begin by researching Sir Piers Pomphrey (who runs a secret society known as AD1 who are a masculinist brotherhood), who has a seemingly flawless reputation, and discover that he knows Geoffrey Thwaites an old flame of Camilla Fritton from the previous film. Camilla tracks him down to ask for help, and he informs her that Sir Piers is the head of a secret society known only as AD1. Geoffrey is persuaded to join forces with the girls of St. Trinian's against Piers.They organize an undercover attempt to break into the headquarters of AD1, recruiting former head girl Kelly (now an M.I.7 agent). They attempt to...