The chosen ones - Scarlett Thomas

THERE IS MAGIC BEYOND THE REALWORLD . . .

EFFIE TRUELOVE has learned to travel through magical books to the Otherworld.
MAXIMILIAN UNDERWOOD, Effie's classmate, is more interested in the dark and forbidden Underworld.

When Effie and Maximilian both mysteriously vanish, their friends Raven, Lexy and Wolf don't know where to turn for help. Raven is a witch and her horse, Echo, has revealed that Effie is in deep danger and time is running out.

To make things worse, Raven's mother, the author Laurel Wilde, is caught up in a plot with the ruthless billionaire Albion Freake, who, it seems, will stop at nothing to become invincible . . .

Where are Effie and Maximilian? Are their disappearances connected?
And can Albion Freake's deadly plan be stopped?