Dirty Work — Reed Farrel Coleman

Gulliver Dowd is a little person in a world of hurt. After his sister, an NYPD policewoman, is murdered, he becomes a licensed PI. Dowd is shocked to discover that his mysterious new client is Nina, his high-school girlfriend and the one true love of his life. But the real surprise is yet to come. Nina hires Gulliver to find her runaway daughter, convincing him to take the case only when she confesses that the missing girl is Dowd's daughter too, the product of their high-school romance.

When he takes the case, Dowd must travel from an exclusive girls' academy to a Mafia don's mansion to seek the answer to his newfound daughter's disappearance. But all is not what it seems. What is the real surprise awaiting Gulliver Dowd?