A seemingly normal detention in a seemingly normal comprehensive school. The valiant teacher battles on with biology revision. She believes that only education will set her pupils free. Outside the classroom, the world is in the middle of a long and bloody war. Despite all her best efforts, all too soon the tide of conflict is lapping at the school gates and one by one pupils and teacher are pulled under, as their hopes and dreams float away from them. But as the teacher has taught them in her biology lesson, like the cockroach, the fittest will survive.