Teenage fantasies of horror in the house next door yield to the reality of a family falling apart--in this YA-ish debut novel from screenwriter Merrick. Nelson Jaqua's 13th summer is also the summer of his discontent. It's 1962; the Portland, Oregon, teenager has been told to mind his little sister Maude all day long, which means no summer job and no joining his friends Cat and Tim in their detective work. The three loners have found common cause in investigating Bobby Shook's disappearance; tomboy Cat is convinced that Bobby's elderly parents have murdered the retarded Bobby and buried him in the basement. Meanwhile, their surveillance is a nice distraction for Cat from her own troubles: her mother has just run off with another man, leaving her alone with her uncommunicative father. But Nelson is in worse shape than Cat: Maude is driving him crazy; his parents, neglecting both him and Maude, are talking divorce; Cat and Tim have unaccountably started dating, cutting him out of the picture; and he has constant headaches. His solution is to break into the Shooks' house. Old man Shook catches him and demonstrates conclusively that there is no dead body: Bobby is in the hospital in a coma. Fortunately for Nelson, both the Shooks are sweethearts, who serve their young intruder blackberry pie and soon become surrogate parents for both Nelson and Maude, giving Cat the opportunity to make major mischief. A dramatic climax involving cops and a drawn gun shocks Nelson's folks into acknowledging their shortcomings. Nelson's efforts to cope with a world suddenly made treacherous by parental love withheld are described with delicacy and humor--in a distinctly above-average example of the coming-of- age genre.