The Midnight Visitor (ebook*)

It's midnight in St Ninian's Haven: Sister Mary Maxwell-Hume makes her nightly call on those near the end of life. As she goes round whispering a prayer over each in turn, some are more aware of her ministrations than others.

For one, however, it's too late. He lies face down on top of another comatose patient, and it's unlikely that he's died of natural causes, given that a brand new Sabatier fish knife is protruding from his back. Meanwhile, for the nun who finds him, there's a further shock: she's known the dead man for most of her life.

But help is at hand. A friend from her past, newly-promoted DI John Knox happens to answer the emergency call to the police. Years before, the nun used to teach him piano. And some other things...