It's murder in the worst degree when an executive at a knife factory is killed with its newest product, a curved blade called the tiger claw. Was Sam Park murdered because of the "private project" he was working on, one that threatened to expose dirty secrets? Ominous message fragments only deepen the mystery. Most perplexing of all is why the dead man's outstretched hand is resting on the open page of a world atlas. Was he naming his killer?

All is not as it seems as Detectives Henry Lau and Janet Lau try to answer these and other questions, leading them to a startling revelation that undercuts everything they thought they knew in a puzzling investigation Henry refers to as "very Agatha Christie."

Elements of the murder recall challenging moments from Henry's distant past. Meanwhile, Janet, his niece and work partner, deals with the aftereffects of a concussion that she struggles to keep from affecting her work on the investigation.