Norman Osborn's violent purges have rid his black-ops squad of all but the most heartless mercenaries - but Songbird, once thought to be among the casualties, has returned for revenge! Taking on a team of the world's most vile super villains single-handedly is more than most heroes can manage, especially when those killers are funded by the government. And although Songbird's former teammates were no angels, this new group is comprised of the most violent sociopaths in the world - each handpicked by Osborn and led by the deadly Yelena Belova, the other Black Widow. Does Songbird have a fighting chance against such impossible odds? It doesn't seem likely. Not until one of the assassins reveals their shocking true identity, and threatens to topple not only the Thunderbolts, but the entire Osborn regime!