In Superman's absence, two new heroes arrive on Earth from out of Kryptonian lore! Following the startling events of "New Krypton," Earth finds itself without Superman! And this world without a Superman is a very dangerous place indeed. The only thing standing between the good (and not-so-good) citizens of Earth and the shadow of doom are the all-new Nightwing and Flamebird. But who are these two heroes who have taken their names from legends of Krypton's past?