Trained in the rites of the spirits to become the Keeper and Seeker of Edgewood, twins Moria and Ashyn are separated during a visit to the Forest of the Dead, where they learn that shadow stalkers have been killing all visitors.

Desperate to outmaneuver the evil Alvar Kitsune, Moria allies with Gavril, while Ashyn discovers that she is the key to a ritual that could reawaken an ancient dragon and turn the tide of the coming battle in their favor.

Everyone says Lauren Tranter is exhausted, that she needs rest. And they're right; with newborn twins, Morgan and Riley, she's never been more tired in her life. But she knows what she saw: that night, in her hospital room, a woman tried to take her babies and replace them with her own...creatures. Yet when the police arrived, they saw no one. Everyone, from her doctor to her husband, thinks she's imagining things. A month passes. And one bright summer...

Back in London, fifteen-year-old twins Sophie and Josh Newman must determine whom they can and cannot trust as they search for both Scatty and an immortal who can teach Josh the magic of fire, while Doctor Dee and Machiavelli continue to seek power.

In the early twentieth century in Swampsea, seventeen-year-old Briony, who can see the spirits that haunt the marshes around their town, feels responsible for her twin sister's horrible injury until a young man enters their lives and exposes secrets that even Briony does not know about.

Fifteen-year-old twins Sophie and Josh Newman continue their magical training in Paris with Nicholas Flamel, Scatty, and the Comte de Sant Germaine, pursued by Doctor Dee and the immortal Niccolo Machiavelli.

In late nineteenth-century New York state, wealthy sixteen-year-old twin sisters Lia and Alice Milthorpe find that they are on opposite sides of an ancient prophecy that has destroyed their parents and seeks to do even more harm.

In Peculiar, Pennsylvania, the supernatural kids, from ghosts to werewolves to witches, attend Yvette I. Koffin's Exceptional School for Supernatural Students (Y.I.K.E.S.S.S.), but while twins Bella and Donna have great powers they struggle at controlling their magic.

When their brother Dashiell dies, twins Ruby and Everett must save one another from his hauntings.

When she was ten years old Kenna discovered that she had the ability to drain the life from another human being, and ever since she has been afraid to touch anyone--but when she uses that power to save her mother and twin sister from an attacker, her mother finally reveals the secret origin of her power, and she is forced to choose between the Kalyptra and a human life.