The Faerie Woods series

Fourteen-year-old Blue (a human) should be upset that his new friends Salix (a Nixie) and Finola (a Faerie) have tricked him into going on another adventure into Faerieland. But he's actually quite excited. Especially since their quest to find the way back to Salix's homeland takes them through the Wherewood, a magical region where lost things go. They encounter confused pets, misplaced homework assignments and mountains of odd socks. But when a misstep leads Blue into the forsaken Witherwood, he comes face to face with an old enemy.

"Blue Jasper is on a hike with his younger siblings, twins Indigo and Violet. One moment the twins are right ahead of him, and the next they are gone. As Blue frantically searches for them, a strange woman appears claiming to be the Faerie Queen Olea of Nearwood and the twins' real mother. Indigo and Violet have been captured by Olea's rival and now, because of a magical pact, Blue must travel through the magical forest of the Crosswood and rescue them before the next sunset. Because the price of a broken Faerie pact must be paid"--Provided by publisher.