Invasores del cielo / Brandon Mull ; traducción de Jorge Rizzo.

Enhanced descriptions from Syndetics:

Cole Randolph solo quería pasar un buen rato con sus amigos en la fiesta de Halloween (y tal vez conocer un poco mejor a Jenna Hunt), pero se verá envuelto en una aventura que nunca antes fue capaz de imaginar: entrará en los Cinco Reinos, un mundo en medio de otros mundos.
Lo que Cole no sabes es que, una vez que entras en el mundo de los Cinco Reinos, es casi imposible salir de él.
Con la magia de los reinos, Cole y su inusual amiga Mira deberán rescatar a sus amigos y encontrar el camino de regreso a casa... antes de que su pasado sea borrado.

ENGLISH DESCRIPTION

Adventure awaits in the Five Kingdoms--come and claim it in this start to a new series from the #1 New York Times bestselling author of the Fablehaven and Beyonders series.

Cole Randolph was just trying to have a fun time with his friends on Halloween (and maybe get to know Jenna Hunt a little better). But when a spooky haunted house turns out to be a portal to something much creepier, Cole finds himself on an adventure on a whole different level.

After Cole sees his friends whisked away to some mysterious place underneath the haunted house, he dives in after them--and ends up in The Outskirts. The Outskirts are made up of five kingdoms that lie between wakefulness and dreaming, reality and imagination, life and death. It's an in-between place. Some people are born there. Some find their way there from our world, or from other worlds.

And once you come to the Outskirts, it's very hard to leave.

With the magic of the Outskirts starting to unravel, it's up to Cole and an unusual girl named Mira to rescue his friends, set things right in the Outskirts, and hopefully find his way back home...before his existence is forgotten.