Mischief Unmanaged

After everything they've done for him- giving up the Marauder's Map in the first place- Harry didn't think to mention the fact that his dad was Prongs? That they'd spent a year being taught by the one and only Moony? When Fred and George find out Sirius's and Lupin's not-so-secret-secret, they prepare to open up a world of mischief on the Chosen One. One-shot. Set during 5th year