When 47-year-old high school teacher Caelum Quirk and his younger wife, Maureen, a school nurse, move to Littleton, Colorado, they both get jobs at Columbine High School. In April 1999, Maureen finds herself in the school library at Columbine, cowering in a cabinet and expecting to be killed, as two vengeful students go on a murderous rampage. Miraculously she survives, but at a cost: she is unable to recover from the trauma.