Piercing the Veil Book Series

Peter Stewart grew up on a unique version of the Arthurian legends taught him by his father, a harebrained quantum physicist. But Peter disbelieves anything which cannot be scientifically explained. Lily Portman is an orphan with a secret: she can see creatures that are invisible to everyone else.  These creatures control every human being she has ever met to varying degrees...until she meets Peter and his father. When a mysterious stranger stages an accident which nearly costs Peter and Lily their lives, Lily learns that she is not crazy after all, and Peter discovers the truth of his father’s stories....

Peter Stewart is a dead ringer for the legendary King Arthur, and because of that, everyone in Carlion believes that he is the Child of the Prophecy, destined to destroy the Shadow Lord. But Peter doesn't want to be a hero; all he wants to be is left alone. Lily Portman also fits the prophecy. Having spent her entire life as an orphan and a misfit, Lily would love nothing more than to be the Child of the Prophecy, so she envies Peter, but she's also developing a crush on him. And it seems to her that he couldn't care less.

The Shadow Lord has the Philosopher’s Stone and, therefore, an army of invincible penumbra. He also possesses the fragments of Excalibur, the legendary sword prophesied to be the instrument of either his own destruction, or that of the Child of the Prophecy. The sword, he knows, requires blood to be reforged, and he knows exactly whose blood he wants. Meanwhile, the Watchers are desperate to steal back the fragments of Excalibur and find out how to reforge them before the Shadow Lord does.