Double double, twins spell trouble... Hunter and Mercy Goode are twin witches, direct descendants of the founder of their town of Goodeville. As their ancestors have done before them, it is now time for the twins to learn what it means to be Gatekeepers—the protectors of the Gates to different underworlds, ancient portals between their world and realms where mythology rules and nightmares come to life. When their mother becomes the first victim...

Hunter and Mercy have had it with each other. After Hunter renounced her god, Tyr, and learned that the warning in the Goode grimoire was wrong, she has decided to cut away from Mercy by moving in with Jax. But little does she know that the new goddess she has pledged herself to has plans for her, whether she likes them or not. Meanwhile, Mercy keeps trying to heal the Gates on her own and shifts her focus to the Egyptian Gate, where she connects...