In a rural English village in the middle of a snowstorm, the unthinkable happens: the school is under siege.

From the wounded headmaster barricaded in the library, to teenage Hannah in love for the first time, to the police psychologist who must identify the gunmen, to the terrified 8-year-old Syrian refugee, to the kids sheltering in the school theatre still rehearsing Macbeth, all must find the courage to stand up to evil and try to save the people they love . . .