Two variations on the locked-room puzzle: the first, a murder in a sealed-off Jacuzzi; the next, a murder in a closed elevator. Charlie Meiklejohn, a former arson inspector, and his wife, Constance, a psychologist, are hired by Bellringer executive Milton Sweetwater to find out who killed the company computer genius Cary and architect Rich--co-designers of Smart House, their all-computer-run brainchild, a creepily well-ordered, Big Brotherish home prototype. Was it Cary's slighted brother Bruce? His wife Beth, ready to divorce him? Company accountant Harry, or attorney Jake? Ex-lover Laura? Maddie, his tippling Mom? Or. . .did the house do it? Complicating the investigation: During the real murders, everyone at Smart House was playing a Cary-rigged game of "Assassin," in which participants "killed" each other for company voting shares, while their every move was logged on a computer. Soon Milton dies, Beth's in jeopardy, as are Constance and Charlie--who finally triumph over the skulduggery with a technical, complex, absolutely fair-play indictment involving computer access, secret passages, voice prints, and popcorn. Great fun for hackers and ratiocination fans; and Charlie and Constance's marriage is enviable--as is their aplomb.