Hades's Promise (Underworld Saga #6)

Therese never expected to find herself in Circe's battlefield again, and this time she fights for things more important than her life.Before Therese and Thanatos can come to terms with the uncertain future of their unborn twins, Poseidon is attacked and both his wife and trident are stolen.Therese is forced to deliver her babies in the midst of an all-out war with enemies more powerful than the Olympians.*Formerly The Gatekeeper's Promise