An acclaimed political author stands accused of the rare crime of 'incitement to disaffection', in other words, encouraging two young soldiers serving in Northen Ireland to desert the army. The prosecution claim that the idea to desert the army only entered the soldier's minds after reading his book, which criticized the way in which the British Army was behaving in the province.

Trooper Dugdale maintains that visiting defendant Parfitt was the catalyst for his and Ronald Fisk's desertion. Major Hughes found Dugdale with Parfitt's book and confiscated. In his absence, Trooper Ronald Fisk's father takes the stand.

Author Arthur Charles Parfitt defends "Trespass Under Arms" and denies the charge of Sedition. His aim was to highlight the effects war has on the civilian population and he denies he paid any part in Trooper William Dugdale going AWOL.