Diana's wedding preparations are interrupted when her fiance Ben receives an urgent plea for help from a reclusive childhood friend in this final volume of the series. A team of men working on a secretive archeological dig on Graham Somener's island off the coast of Maine have all been poisoned. When one is murdered in a diving accident and Graham refuses to call in the police, Diana and Ben fear he may have fallen under the spell of a confidence woman posing as an archeologist from the Peabody Museum. Their investigations threaten Ben's friendship and imperil Diana's life before the conundrum is finally solved.