Mercer's second Ariel Gold thriller has a fetching cast and an ingenious plot device. True tension is the only missing element in this promising series. In Fast Forward (1995), Ariel Gold lost her memory in a Los Angeles explosion that coincidentally killed her twin sister Jane-- a sister Ariel didn't know she had. While coping with her amnesia, Ariel, who was raised separately from Jane by unloving adoptive parents, mysteriously became transformed into the person she might have been had she been raised in a good home. She lost 30 pounds, did better at her job as a producer for an investigative TV show called Open File, started using makeup, and became outgoing and confident. So changed did she become in fact that her thrice- divorced boss, Henry Heller, who had never given her a second glance, is now in love with her; and her new-found grandfather, a wealthy southerner, is showering her with attention. This second installment begins near his house on Kiawah Island in South Carolina, where Ariel meets John William Barron, an old friend of Jane's, who is discovered the following day dead of carbon-monoxide poisoning in what is supposedly a suicide. Because of John William's connection to her sister, Ariel investigates the mysterious circumstances of his death and the gothic goings-on of his scandal-ridden Charleston family (his father was also supposedly a suicide), while on the other coast Henry takes care of her dogs and conducts his own inquiries into the disappearance of a computer genius, the founder of MicroStar. The dual mysteries, solved in interweaving chapters, work against the build-up of suspense in either one, and an attempt to bring an L.A. villain to South Carolina never becomes integrated into the story. No page-turner, but Mercer nevertheless is a bright author with a fine sense of humanity and some ideas that may very well mature.