Sensible Portia Harris falls in love with goregous blond Chris Stryker at first sight and moves into his old house in Park Slope (Brooklyn) three weeks later, despite the Manhattan-chauvinism of her friends. But there is something distinctly creepy about the place; it seems to be haunted by a 17th-century house previously on the site and by the murder of a young pregnant girl, Margarietje, that occurred therein. Then the murderess, ""Old Wedgefoot,"" not only invades Portia's dreams but nearly kills her with a razorblade. And Chris keeps going into a daze and speaking Dutch and calling Portia ""Grietje."" Obviously, something must be done. Research at the historical society brings all to light, but too late: Chris, a photographer by trade and obsession, has somehow been managing to take pictures of the vanished house through a ""time-warp,"" and now he's even taking shots of its long-dead inhabitants, including one ancestor who's trying to use the present to alter the past and thereby prevent the murder of his beloved Margarietje. For those who like their romance mixed with the sneaky supernatural, this is more chilling and less gruesome than most.