A rare shopping trip for the Reverend Mother ends in brutal murder in this absorbing historical mystery.

Despite its regal name, the Queen's Old Castle is nothing but a low-grade department store, housed within the decrepit walls of what was once a medieval castle, built at the harbour entrance to Cork city. On her first visit for fifty years, the Reverend Mother is struck by how little has changed - apart, that is, from the strange smell of gas ... But when the store's owner staggers from his office and topples over the railings to his death, Mother Aquinas is once again drawn into a baffling murder investigation where suspects are all too plentiful.

An unpopular man, Joseph Fitzwilliam had been disliked and feared by all who worked for him. And when the contents of his will are revealed, suspicion widens to include his own family ...