The ties between women can run as deep as the ocean-but so can the secrets. For 20 years, Kayla, Antoinette and Val have performed their own special summer ritual. Once a year, the old friends put aside their daily, separate lives to drink champagne, swap stories and swim naked under the Nantucket stars. But on one of those bonding nights, one of their trio swims out from the shore and doesn't return. After the surviving friends emerge from their...