Shadow of the Moon

Drake thinks his twin sister is better than him at everything. Stella gets all the gold stars. He awakes one night to see a strange light all around her. And the next day at school, when Drake's teacher transforms into a fiery creature, he knows they are in this mystery together.
The creature warns Drake that all light will soon fail, and unless it can be restored, the universe will be lost. Together with their friend Sherman, they race towards the centre of a solar eclipse's path of totality. They are sucked through the ring of last light into a world of complete darkness.
Thankfully, Sherman has brought along a jar of glowing fireflies. In its flickering light bizarre landscapes unfold, full of ancient and mythical creatures. The trio must find their way through the forbidding Caves of Insanity, the dreary Gloom Forest and travel the eerie Murk Sea in search of the source of all light, that lies encased in stone. Before they find the stone they are separated, and Drake goes on alone. It is then he faces his greatest obstacle, and must choose between Stella and Umbra, the Shadowmaster, who offers him greatness in exchange for her betrayal.