The Sideways Hole

Where do all our shadows go when they flee from the light?
Down, down, they slither and slide, through the cracks in the pavement and the holes in the floor. Draining down to the dark far, far below. There the Krepuscs (as they call themselves) sit and wait, getting quite bored and ever more impatient. But mostly bored. Like all evil beings they are bent on destruction and seek the enslavement of all that differs from themselves. All they need is a way back to the surface...
By chance, or perhaps design, so too our young hero finds himself falling down, down, down to Thiluwet, the realm of shadows. Faced with an army of hideous beasts, unusually poor lighting and absolutely no idea what is going on, it is up to Tobias to stop the rising tide of darkness.
Can Tobias, a dumpy boy of fourteen, prevent the world from being enslaved to its own shadow? Even with the help of a few fellow friends he finds along the way, things look grim. However, fortunately for us, Tobias is far from your average teenager.