After the shocking events of The Crossing, Earth's Mightiest Heroes finally have a chance to settle down and look forward to the future. But the air of mistrust created by Iron Man's betrayal still lingers inside their Fifth Avenue townhouse. When a mysterious cyborg prowls the mansion's hallways late at night, the tension among the heroes only rises! Who is picking off the Avengers one by one? Could it be Madame Masque? Or perhaps another rogue teammate?