Wild Thing by Josh Bazell

It's hard to find work as a doctor when using your real name will get you killed. So hard that when a reclusive billionaire offers Dr. Peter Brown, aka Pietro Brnwa, a job accompanying a sexy but self-destructive paleontologist on the world's worst field assignment, Brown has no real choice but to say yes. Even if it means that an army of murderers, mobsters, and international drug dealers -- not to mention the occasional lake monster -- are about to have a serious Pietro Brnwa problem.

Facing new and old monsters alike, Dr. Brnwa's story continues in this darkly funny and lightning-paced follow up to Josh Bazell's bestselling debut.