A young boy, Max, and his imaginary best friend, Marco, are inseparable. When Max begins to have nightmares about a monster coming for Marco, he realizes his nightmares are not dreams at all, but reality, and that his time with Marco is coming to an end--unless there's something Max can do about it. Max knows he must enter his nightmare and prepare himself for the ultimate battle as he spends what could be his last day with his best friend