Robert B. Parker's Grudge Match

Robert B. Parker's beloved PI Sunny Randall returns on a case that blurs the line between friend and foe...and if Sunny can't tell the difference, the consequences may be deadly. When Sunny's long-time gangster associate Tony Marcus comes to her for help, Sunny is surprised--after all, she double crossed him on a recent deal, and their relationship is on shakier ground than ever. But the way Tony figures it, Sunny owes him, and Sunny's willing to consider his case if it will clear the slate.
Tony's trusted girlfriend and business partner has vanished, appears to have left in a hurry, and he has no idea why. He just wants to talk to her, he says, but first he needs Sunny to track her down. While Sunny isn't willing to trust his good intentions, the missing woman intrigues her--against all odds, she's risen to a position of power in Tony's criminal enterprise. Sunny can't help but admire her, and if this woman's in a jam, Sunny would like to help.
But when a witness is murdered hours after speaking to Sunny, it's clear there's more at stake than just Tony's love life. Someone--maybe even Tony himself--doesn't want this woman on the loose...and will go to any lengths to make sure she stays silent.