A burnt-out American doper, fresh from a Bolivian prison, starts out conning a naive social worker by helping her find her magician brother--and ends up conducting her on a tour of the hell that is the coca trade, while gradually recovering his humanity. Ringing new changes on the legacy of Chandler and Traven, this first novel by Jacobs (stories: A Cast of Spaniards, not reviewed), a longtime foreign-service functionary, matches noirish Roger, the Stone Cowboy, whose drug abuse has shorted out body and soul, with Agnes, a prissy Yankee social worker who's come in search of her magician brother Jonathan, now the pet of a major cocaine dealer. Narrating in the louche voice familiar to drug writers from Robert Stone to Jay McInerney, Roger takes Agnes backstage in the so- called war on drugs. Of course, the only way to get to Jonathan-- who seems to be seeking the real magic that fled North America with the coming of the Industrial Revolution--is to descend, and so our odd couple will hear Zen wisdom from the mouths of peasants, go for a wild ride with a mad revolutionary radio-broadcaster, work as forced laborers smashing coca leaves in a jungle pit for a vicious middleman, undergo interrogation and beatings by DEA henchmen--and finally travel with the brother and the druglord to the top of an Andean peak, where the last real magician lives. There, Jonathan will get his wish (he becomes a bird as the druglord executes him), and, like the Cowardly Lion, Roger will get to ask the god La Pachamama for his own wish: ``Give me back my heart.'' An unusual love story, to say the least--a little bit as if The African Queen were mixed with Panic in Needle Park--and an impressive debut from a writer with a generous imagination and a daring, if deeply weird, sense of character and fate.