 Ronnie is annoyed with Calley because she lied that she was round her house without telling her first. Just who is the mystery man that Calley is seeing? The third formers take a trip to the Canal to collect pollution samples Justine tries valiantly to become friends with Tegs again, but it s an uphill struggle and he refuses to meet her boyfriend. Matthew confides in Tegs to tell him that his family is strapped for cash. Trevor gathers his friends together for some card games with Rod - but the caretaker seems awfully lucky, and takes the sixth formers to the cleaners. Tegs introduces Matthew to the art of breaking-and-entering, going into the caretaker s office with the objective of taking Mr. Griffiths army photograph, for a laugh. Tegs grabs the framed photo and the two enjoy a cup of tea. When Mr. Griffiths comes back unexpectedly, Matthew hides under the table. When the two escape back onto the roof, Tegs slips and twists his ankle, dropping the photo, which smashes. Mrs. Monroe manages to get herself locked into the Stationery Store so attracts the attention of Tegs and Matthew as they pass by. They go to Mr. Hargreaves s office to try to find where the Deputy Head is likely to be, and notice a similar frame to the one they broke, so Tegs grabs it. Mr. Griffiths gives Tegs permission to get the spare Stationery Store key from his office, which is the opportunity he needs to put the photo back in Mr. Hargreaves s frame, ditching the old photo behind the radiator. Unfortunately, Mr. Mackenzie waylays Tegs and Matthew before they can get back to the imprisoned Mrs. Monroe....