The Shadowed Manse - The Arthur Paladin Chronicles, #1

"A must-read for fans of Doctor Who and Percy Jackson. Prepare to fall in love with this universe-spanning, high-octane, science-fantasy adventure." Arthur Paladin doesn't fit in. Not at home with the ultra-strict grandmother who had to raise him after his mother died and his dad disappeared. And not at school where the teachers think he's nothing but trouble and the other kids think he's a freak.
But every night he dreams about learning amazing things, the sort of things you need to know to save the world. Deep down, he knows he's destined for something greater than 7th grade math.   On the verge of his grandmother sending him to military school, Arthur gets in a fight with his "perfect" cousin, which leads to the mysterious plate over his heart getting broken, which leads to . his whole world turning upside down.
 Shadow creatures appear out of nowhere to kill him. An angelic being from another dimension begs for his help. He gets locked in a house that looks like an English cottage on the outside but is actually a mansion on the inside, and it's traveling away from Earth, across the universe. The house is packed with shadowy monsters, and he's only got Morgan Apple to help him - Morgan Apple who apparently sits beside him every day just to call him a moron. And that's when life gets really weird.
That's when Arthur finds out he's the next Multiversal Paladin.