Running on Moonlight

When Jessie and her friend Pete sneak into August Erasmus's lab, they mean to rescue his abused animals. Instead they find a boy in a cage. Horrified, they set him free, and Jessie promises to hide him.
The strange, pale boy is August's son, Lucan. He knows he's strange. He can't bear the sun, sleeps by day, bursts with energy by night, and can only digest raw blood. Like August, he has the family disease: nothing sinister about it.
But sinister does describe August's lizard-like hounds, and the grey-faced servant who haunts Jessie's dreams of her parents' death.
None of it matters when she runs with Lucan under the moon. Her senses sharpen. Energy sizzles through her body. But deep down, a terrible hunger grows. She recalls how her blood mixed with Lucan's during the escape, when their cut hands clasped.
Lucan finally confronts August, but who wins? And Jessie, fighting to stay human, has only Pete's loyalty and her own new powers to pit against the oldest, deadliest enemy of all.