Mine was using a few bits of the stimulus. I was somehow trying to incorporate the shell into it, so i set it at the beach, where there's this guy and this girl (incoming cliche). The wind's fairly strong and he almost loses his hat to it, the girl says 'nice catch'. the guy jokes that if he didn't catch it, she'd have to go get it for him. In response, she playfully punches him, which brings about a flashback that is the bulk of the story, where the guy is always getting beaten up and has no friends. He then moves school in year 7 and finds that kids from his old school have ended up here too, and are trying to beat him up again. Then the girl steps in front of the bullies and threatens to tell the teacher (ooh scary!), and then the guy and girl become friends, then bf/gf, and then it cuts back to the beach. They then go into the water for a swim, and the guy steps on something. He picks up a shell (oh god, someone who used the stimulus), and ponders at its lack of inhabitant, and how it had moved on. I told this to my english tutor later and she thought it was a metaphor for the guy 'coming out of his shell'.
I certainly hope that's what the markers think.