Born in a tenement in Dublin in 1874, Mallin joined the British Army as a drummer at the age of fourteen. On leaving the army he became a silk weaver and in 1908 secretary of the Silk Weaver's Trade Union.

By 1914 he was Chief of Staff of the socialist Irish Citizen Army, second in command to James Connolly. During Easter week 1916, Mallin commanded a garrison of rebels in St Stephen's Green and the Royal College of Surgeons. He was executed in Kilmainham Goal on 8 May.

This book explores what brought a socialist, a devout Catholic, a temperance advocate, husband to a pregnant wife, and father of four young children - a man with much to lose - to risk his life and wage war against the British in 1916.