As the tide of public opinion turns enexorably against Marvel's heroes, the gears of civil war threaten to crush the young heroes known as the Runaways. But when the Young Avengers offer their assistance, can the Runaways believe they are on the same side? The warden of the prison called the cube wants both teams taken down, and he sends his most powerful weapon to do it: Noh-Varr, the young kree know as Marvel Boy! Can the two teams put aside their differences and work together to free their captured teammates?