Quinnan ignores a plea for help from a mysterious opera singer whilst out on patrol, but later regrets his actions and ignores a number of shouts whilst trying to find her. Meanwhile, Holmes is dealing with a personal request from Brownlow, who has been asked by a local judge to investigate a number of threatening letters sent to him. Holmes and Quinnan soon come to realise that they are chasing the shady criminal. A new face at Sun Hill is causing quite a stir, in the form of Scottish DC Duncan Lennox. Lennox offers to provide Holmes assistance on the case after she discovers he has a personal acquaintance with the judge. A showdown at a local opera house goes awry when Stamp bursts in unexpectedly.