Nighthawk warns the Defenders of the return of the Squadron Sinister, which means only one thing - super-team showdown!
Nighthawk, whose career so far has been that of a criminal, watches Dr. Strange's Sanctum Sanctorum. He breaks in with his wing lasers and says he needs to talk to the Defenders.
They are angry that he broke in, and attack, but Nighthawk amazingly manages to dodge multiple blows from the Hulk and Valkyrie, making them look foolish. Strange finally convinces his friends to listen.
Nighthawk explains that he got a note threatening to expose his criminal past unless he showed up in a secluded spot one night. He did, and finds his previous allies, Dr. Spectrum, Hyperion, and the Whizzer--the Squadron Sinister. They needed him for their upcoming job coordinated by a godlike being, Nebulon. Nighthawk tries to refuse, but Nebulon uses his powers to paralyze him until he agrees to help.
NIghthawk eventually escaped and tried to warn the Avengers, but was unable to. He next went to the Defenders (last issue, in the trenchcoat) but couldn't find them. Now he is glad to have found them, because, as he explains, Hyperion "sold" Nebulon the Earth, and they plan to flood it by melting the Arctic ice cap. However, Nebulon realizes that Nighthawk is selling them out, and he disappears in a flash.
Strange, concerned with the danger, teleports Namor to their side for help, despite the fact that he quit the Defenders two issues ago, and specifically refuses to help now. Once they explain the problem, however, he agrees to lend his aid.
They arrive in the Arctic and attack the Squadron Sinister. They do well, until Nebulon shows up and puts them all in a force bubble.