WENDY DUNILAVY is desperately trying to hold her family together. But with her politician husband in prison for corruption and her son. Dylan, the former child actor, running unsupervised through the orderly avenues of northwest Washington, she may not have enough muscle for the task. And that's before the first sighting of the mysterious Chagwa, a famished and unruly menace that not only breaks up the all-important Beltway soirees but also seems to have intentions toward Dylan. Life might be easier if she weren't addicted to sedatives like the rest of the frightened population. Life might be easier if it weren't always a diet of misery, hilarity, longing and surprise in a nation of hucksters, self-deluding lobbyists and pundits. Known for her "haunting and inventive" story telling "(Harper's Bazaar), her laugh-out-loud repartee, and her surreal transfigurations of the commonplace, Julia Slavin has unleashed a hilarious and disturbing tale where the reach of fantasy is as long as the arm of the federal government.