In 1938, three orphans--Theo, Carl, and Ian, ages ten to thirteen--lead three teachers through a portal that takes them from Dover, England, to Morocco in their quest to locate six silver boxes before the ancient prophecies therein are found by the evil Demogorgon's offspring.

Evelyn heads to Mt. Olympus Theme Park to celebrate her winning a hair design content, where she travels through a mirror in Athena's Hall of Mirrors to a myth; but when she meets Perseus on a mission to behead Medusa, Evelyn wants to try a more creative approach.

In 1940, when Delphi Keep's taken over by the Royal Navy as a communications outpost, Ian, Theo, and Carl dread being evacuated to the earl's winter residence where they'll no longer be protected, but are even more concerned about deciphering the third prophecy and identifying the Secret Keeper.

"Ava Baldwin has always tried to keep her anger in check, just like her mom taught her. But when know-it-all classmate Owen King tries to speak over her yet again, Ava explodes . . . and Owen freezes, becoming totally unresponsive. Although Owen recovers, Ava's parents whisk her off to her mother’s alma mater, the Accademia del Forte, a mysterious international boarding school in Venice. There, Ava and her brother, Jax, discover that the Olympian...