Henry Hallward, editor of the Sydney Chronicle, is a thorn in the side of the colonial administration with his agitations for greater rights for convicts and his criticism of the governor. He's been imprisoned several times for criminal libel, and during one detention, he is shot dead.
Monsarrat and Mrs Mulrooney are sent to investigate, but after Monsarrat meets with Colonel Duchamp, Governor Darling's right-hand man, it becomes clear they are on their own in solving this murder.
As the duo meets other characters whose lives have touched that of brave Hallward, they realise the scope of their enquiries must be broad. There is Gerald Mobbs, editor of the Chronicle's rival newspaper, the Colonial Flyer, which some call a mouthpiece of the administration. There is Duchamp's sister, Henrietta, who seems to want to befriend Mrs Mulrooney, but also to have ulterior motives. There is Albert Bancroft, an éminence grise who may, or may not, own the house opposite the gaol, from where the murderous shot was fired.
The undaunted pair must sift through these suspects, aware that at any moment Duchamp could ignominiously dismiss them, leaving Hallward's murder unsolved and the freedom of the colony's press in grave jeopardy.