The book "On the Edge" follows two brothers, Dillon aged 15 and Robbie aged 10, as their mentally ill ex-serviceman father takes them on a suspicious holiday trip which raises concerns. The story is told from the perspective of the two boys as they deal with their unstable father on the trip from their home to Gardle Head. In the end, the father commits suicide, leaving the boys orphaned but survived, having been found by their mother and her boyfriend at the funeral.