Daphne returns to the island to save her best friend, Cam, and the other "Calibans" who've been brainwashed by Dr. Gray, but, once again, things aren't what they seem. Daphne's entire world comes crashing down along with the Purgatorium when federal ATF officers arrive with a warrant during a dangerous exercise. What she believed to be so isn't, and the blurry line between art and reality leaves her reeling.

Seventeen year-old Daphne Janus is surprised when her parents agree to let her accompany her friend to a getaway resort on an island off the coast of California. They haven't let her out of their sight since last New Year's Eve, when she could no longer stand the way they looked at her. Her sister would still be alive if it weren't for Daphne. Her friend, Cam, takes her to a mostly uninhabited island with a wildlife preserve on one side and Chumash Indian ruins on the “haunted” side. Daphne decides she will have one last "hurrah" before she finishes what she started last New Year's Eve. However, things seldom go as planned... The resort is beautiful, the beach pristine, and the views from the headland amazing. The only thing missing is the boyfriend who left her when she could no longer love anyone. Then strange things begin to happen on the island that soon have Daphne running for her life. She eventually learns that her parents have sent her for experimental "suicide therapy," but when her horse bucks her off during a trail ride and she becomes lost on the haunted side of the island, she wonders if her parents have sent her there to help her or to punish her.

Gertie has become friends, and has possibly fallen in love, with both a demigod and a vampire, who happen to be at war. Although she sympathizes with the vampire uprising and has even become a vampire herself, she distrusts the leaders, especially when they plan to kill humans to cull out the demigods before ambushing them. As the three unlikely friends discover that neither side is perfectly good or evil or right or wrong, they work together to try to bring about the best outcome; but, when their parents and the gods undermine their efforts and hang them out to dry, the three teens realize they're on their own and no one will save them.

In The Gatekeeper's Sons, Therese and Thanatos, the god of death, met and fell in love. In The Gatekeeper's Challenge, they did everything they could to be together, even break an oath on the River Styx. But the Olympians don't tolerate oath-breakers. In this third book in the saga, The Gatekeeper's Daughter, Therese may have finally succeeded in becoming a goddess, but if she wants to remain one, she'll not only have to discover her unique purpose, but also make some allies among the gods. Artemis sends her on a seemingly impossible quest across the world, while Than searches for a way to appease Ares. To make matters worse, her baby sister's life depends on the outcome of her quest.