Blair Underwood (yes, the actor) joins husband-and-wife writers Tananarive Due and Steven Barnes for Casanegra the first in a series of urban mysteries laced with hardcore action (read: sex). Tennyson Hardwick is a handsome ex-Hollywood gigolo who gets tangled in a web of prostitution, Smith & Wesson-toting rappers, and shady music execs when an old client turns up dead the day after a steamy encounter. Although mixed metaphors fly like bullets (''I felt Death blow on my face like hot wind from a speeding train''), the pace is taut, the dialogue is snappy, and it's hard not to fall for Underwood's fallen hero. B

