Not by Sight

A magical green gate
A mysterious stranger
A magnificent secret
Twelve-year-old Hannah Walker was just trying to have a fun time hiking in Maine with her father and brother (and maybe play some guitar). But when a desperate cry for help is heard over the ocean, Hannah finds herself on the adventure of a lifetime.
She rescues a mysterious bird-girl who came to Earth with a secret. When the bird-girl asks Hannah to go on a boat ride with her friends, a violent storm sinks their ship, and a magical green gate appears shimmering on the water. Hannah and her friends are swept through the gate to a land teeming with magic. Once on shore, Earth appears in the sky, and the spider-lobsters start biting. And when the Earth fades away, you can't go home.
It doesn't take long for Hannah to realize something is eerily familiar with this strange world. Had she read about this place in her dad's books? The people and the creatures here have been hiding a long-kept secret about Hannah, something amazing, something others would kill for.
It's up to Hannah, her fearless brother Duncan, and the bird-girl to save the planet from a terrible fate and find a way home for her friends. Her daring adventure through volcanic explosions and battles with monstrous creatures will leave the planet breathless, but she must hurry before the green gate closes forever.