When Hobart Penny is found dead in his apartment, the cops think that his pet cat, an adult female tiger, attacked the reclusive elderly billionaire. But it soon becomes clear that the beast that killed the eccentric inventor is all too human. Digging into the victim's life, Decker and his colleagues, Detectives Marge Dunn and Scott Oliver, discover that Penny was an exceptionally peculiar man with exotic tastes, including kinky sex with call girls. Following a trail of clues that leads from a wildlife sanctuary in the San Bernardino Mountains to the wild nightlife of Las Vegas, the LAPD detectives are left juggling too many suspects and too few answers. To break open a case involving the two most primal instincts, sex and murder, Decker wrestles with a difficult choice. Should he turn to a man with expert knowledge of both, Chris Donatti, the dangerous man who also happens to be the father of Decker's foster son, Gabriel Whitman, a boy not without his own problems?