100 Cupboards (100 Cupboards Book 1‪)‬

Readers who love Percy Jackson, the Unwanteds, and Beyonders will discover that 100 cupboards mean 100 opportunities for adventure! The bestselling and highly acclaimed 100 Cupboards series starts here.
 
What dangers are locked behind the cupboard doors? Henry isn’t brave, but when he hears a thumping and scratching on the other side of his bedroom wall, he can’t ignore it. He scrapes off the plaster and discovers mysterious doors—cupboards of all different shapes and sizes. Through one he sees a glowing room and a man strolling back and forth. Through another he sees only darkness and feels the cold sense that something isn’t right. When his cousin Henrietta boldly travels into the worlds beyond the cupboards, it’s up to Henry to follow her. Now that he’s opened the doors, can he keep the evil inside from coming through?
 
"A must-read series." —The Washington Post