All in the Family (Book 4)

"The dark blue book was thicker than before, but as it had the number four in a lighter shade of the same color emblazoned on its spine he was sure it was the one. Even without previous experience, it still gave off a magical energy as blatant as the tension filling the tiny area." Marauders, Jilly, Wolfstar. Heavy on the Peter and Regulus arc. Ch. 1- Frank Bryce's Home