"A History of Violence" is the 865th episode of Casualty and the 42nd episode of the 27th series. It was preceded by "Letting Go" and followed by "Secrets and Lies". The episode was directed by Karl Neilson and written by Emma Goodwin.
A man gives chase to a hoodie who has snatched his mobile and laptop bag, and in the ensuing scuffle he picks up a broken bottle and stabs the robber - only realising too late she is a young woman. But their story only becomes more complicated when both of them end up in the ED. Meanwhile, a mother brings in her eight-year-old son with a broken arm, having fallen off a climbing frame - but Tom becomes suspicious when he sees bruises consistent with grabbing on the boy's shoulder - and Louise is angry with Big Mac for taking pity on a homeless man.