A neat short-story idea--stretched out, with stilted dialogue and overheated prose, to a so-so, often implausible mini-suspense-novel. Suburban housewife Molly, after five years of hearing next-door neighbor Ruth's child-beatings, finally gets fed up, goes over to confront the violent, threatening Ruth . . . and accidentally kills her with a self-defensive push. Molly, who narrates, panics: she digs up her back garden; she gathers up Ruth's belongings; with help from Ruth's bewildered husband Ralph (who seems to think that his daughter killed Ruth), she buries the body, faking Ruth's disappearance. And the novel, alternating between traumatized Molly and her bewildered narrator-husband John, covers the next few years: the police investigation into Ruth's ""disappearance""; Molly's increasing madness--obsessively guarding her garden, talking to dead Ruth, fearing that her secret will be uncovered; and John's increasing exasperation with his ill, crazy, numb wife (who mysteriously refuses to sell their house when a huge-money offer is made). Finally, then, John falls in love with a librarian, Molly has breakdowns, and--when Ruth's hubby Ralph (now remarrying) is accused of the murder--Molly at last decides to confess. The exhumation of the body, however, reveals a nice little twist . . . Molly's behavior is less than credible throughout. And the writing is highly uneven. But, with some good ironic effects in the split narration, the clever plot notion here will carry some suspense-readers right along.