The Fifth Heart is a fascinating historical mystery that blurs the line between fact and fiction. Simmons pairs up everyone's favorite detective, Sherlock Holmes, with an unlikely companion: The American writer Henry James.

A depressed James joins forces with a slightly mad Holmes, who faked his own death two years prior, and has used his incredible powers of deduction to convince himself he is actually a mere fictional character. The two embark on a trip to America to investigate the suicide of James' old friend Clover Adams, setting them into a world of intrigue and danger within the Five of Hearts, Washington's most powerful and exclusive salon.

Subtle, tongue-in-cheek ironies and references to both real and imagined characters abound in Simmons' madcap reimagining.