An 18-year old girl has been missing for weeks. By now, after being headline news for so long, everyone is familiar with her high school photo. So, if a 63 year-old doctor of genetics whose habit is studying faces in public thinks she's just seen the missing teenager you have to take it seriously. To make certain, she and her husband -- an ob-gyn doctor -- follow the girl who is walking with a man. They pick up their pace, as though aware of being spotted, heading for the train station. When Dr. Edna Skylar chases and confronts Katie Rochester they stare at each other. "Please," the missing girl says in a frantic whisper. "You can't tell anybody you saw me." A moment later she's on the train and gone.

Which leaves Edna with a big question. What should she do about it?

In any case, this is not the "promise" of the title. Edna made no promise. That comes on the night Myron Bolitar -- a hero we haven't heard from in author Harlan Coben's case files for something like 7 years -- throws a soiree for his friends and neighbors. Running low on ice, he goes down to the basement and finds two local teen age girls chatting -- high school seniors Erin Wilder and Aimee Biel. When they become aware of his presence he becomes Mr. Casual, playing cool.

After answering the girls' semi-embarassing questions about what ended his superstar basketball career the subject turns to something he overheard them say -- beer and shots and driving under the influence. This is where the big hero plays protector of the potentially vulnerable. "If you're ever in a bind... Promise me. You'll call me. I'll come and pick you up. Promise me."

It was on impulse, but it isn't long, maybe a night or so later when, at 2:17 AM, Myron is awakened by a phone call from Aimee, pleading for a ride. He dresses, picks her up and drops her at a house in Ridgewood, a nearby town. Then, She then goes missing, and when Loren Muse, a cop, learns that Aimee had used the exact same ATM machine that Katie Rochester had before disappearing and that Aimee is 3 months pregnant, new fears are aroused. But however much is learned from there, no explanation seems to fit.

Myron's business as an entertainment agent is basically put on hold as he wraps himself up in the mystery and pursues it like any P.I. (only unpaid). Aided by Esperanza and sidekick Win. She's his beloved office manager and ex-pro wrestler Esperanza and Win is as lethally efficient a partner in vigilante justice as you'll find in the literature. (Walter Mosley's Fearless comes to mind).

Win's capabilities are put most excruciatingly to the test when The Twins -- two of the most vicious psychopaths who were ever hired by the mob are closing in on Myron whom they've subdued. Myron is no pantywaist when it comes to martial arts. He's big and very fast, But these killers get him into a position where, in another minute, he would be rendered into nothing more than a barely breathing hunk of meat.

But the normal precincts of crime don't play their usual dominant part in this mystery yarn that probably resembles an Agatha Christie whodunit more than a Michael Connelly thriller. Coben takes us on a twisting path marked out by wierdly devious players: teachers, new boyfriends, old, rejected ones, parents, a hoodlum parent, and a stream of red herrings. The clues are so logic-challenged that it takes pages of narrative to sort out the motivations and behaviors once the journey reaches resolution. If anyone can do this kind of complex, as any reader of Coben's opus will tell you, Coben is the man to pull it off.