As "Death Vows" opens, Strachey, a hard-boiled detective in Albany, N.Y., is enlisted to investigate the mysterious Barry Fields, who may or may not be a violent con man and gold digger, preparing to marry an older man named Bill Moore just over the Massachusetts state line in the Berkshires. (If, in fact, those are their real names. Which they're not.) The investigation gets complicated when someone kills Strachey's client, sleazy busybody Jim Sturdivant. (Yes, that's technically his real name, but it hides more than it reveals about his past.)There's only one couple in "Death Vows" whose connection is honest, public and lacking ulterior motives: Strachey and his partner, Timothy Callahan. He serves as Strachey's sounding board, support system and confidant. He doesn't let Strachey get away with anything, matching him quip for quip, same as any good partner. But since they live in New York, they can't get married. If that changes, Stevenson will surely write about it, with the snappiest wedding vows you've ever heard.