Former marine Maggie Riley has just set sail for the Caribbean, ready for a little R&R on her 40-foot boat before starting a work assignment in Dominica. Then Cole Thatcher appears. Sexy, naked - and possibly nuts - Cole turns out to be an archaeologist searching for the wreckage from a World War II submarine that may hold millions in gold coins and classified documents from a powerful inner circle of the secret society Skull and Bones.

Maggie Riley has settled into her new life in Thailand, working aboard her sailboat and doing her best to leave the past behind. When she receives a letter from a World War II vet claiming to have served with her grandfather who went missing in action, Riley is once again pulled into the intrigue that tore her family apart and led to the disappearance of her former search partner - and the love of her life.

Shipwreck hunters Maggie Riley and Cole Thatcher are no strangers to the mysteries hidden beneath the seas. They've uncovered artifacts with secrets that powerful interests would do anything to control - and they're about to do it again. As the newly engaged couple prepares to set sail, Cole suspects they are being followed. While he tries to unravel a coded message that hints at a treasure jealously guarded by an ancient society, a bomb is discovered on the couple's yacht.