In the summer after Harry's sixth year, Harry and Remus uncover a section of the Marauder's Map which has been hidden for the past twenty years, releasing a carbon copy of sixteen-year-old Sirius Black from its depths. As they prepare for the impending war, Sirius must find a place for himself in this new world, Harry must find a way to destroy Voldemort, and Remus must face his own past while trying to build a tenuous future with Tonks.