 Someone is hiding out in Grange Hill, carefully avoiding being seen by the caretaker, Mr. Griffiths - but his suspicions are aroused by the open window. When Mr. Bronson arrives, and drops a sheaf of papers, there s a tacit agreement among the watching students, and no-one helps to pick them up. Mr. Bronson seems withdrawn - he tells Mr. Mackenzie he can t go on the Isle of Wight trip. Trevor hides himself away with a couple of cans of lager - later Ziggy and Robbie find him outside, legless and hide him in the gym while he sobers up. Susi s catalogue clothes come back from the dry cleaners - clean but with various defects that make them no longer "new". Mandy tries to persuade Mrs. McClusky to allow motorbikes to be brought inside school to stop them being stolen or damaged. She offers the idea that the standard of driving can be monitored if bikes are brought in. Ziggy and Robbie go to check on Trevor, but the self-defence class is starting and they have to hide behind the curtain. Unfortunately, Ziggy sneezes, and Mr. Robson hauls them out. At the end of the day, Mr. Griffiths locks the school up, but inside, a shadowy figure watches him leave...