Mr. Howe's Final Victim - Marshall Drummond Case Files, #13

Loose ends never sit well with Marshall Drummond, so when most of his case regarding the strange Mr. Howe has finished, he still has one leftover clue to deal with -- a bizarre coin etched with an odd symbol. But what starts as a simple closing of a case turns into a horrifying end that will linger in Drummond for years to come.