Synopsis
The being known as Nebulon has been judged by the High Tribunal of his race for his multiple crimes of interference with Earth (as seen in various issue of Defenders). He is now exiled to Earth, restricted to the humanoid body he assumed, and reduced to less than half of his celestial power. Or he can choose the honourable option of suicide.
Summoning his diminished power he manages to teleport to Dr Strange's Sanctum, blaming him and the Defenders. The Doctor isn't in, so Nebulon starts to take his rage out on his servant Wong. But then belatedly accepts that the fault lies in himself, and teleports away.
Thor is flying over the Himalayas seeking solitude, where he finds the despairing alien sitting on a peak. The repentant alien tells the Thunder God his tale and Thor promises the Avengers will help him make a home on Earth. But as they fly away we see that someone in a female version of Nebulon's glittering body has been watching them.
In Avengers Mansion we find Captain America as usual working out. Wasp comes to gather him for the emergency meeting that Thor has called, where they find Iron Man irritated that he's had to abandon his duties as Tony Stark.
Nebulon teleports himself and Thor into the meeting room. The Golden Avenger is immediately suspicious because he knows of the alien's past misdeeds. Cap and Wasp hold him back while they wait for an explanation. When this is given Jan and Steve are willing to give Nebulon a chance, and Tony grudgingly agrees with reservations.
But the love-in is interrupted by the arrival of 4 Defenders:- Beast, Gargoyle, Silver Surfer and Valkyrie. They are here to take up arms against their old enemy, although Gargoyle is more willing to try jaw rather than war. He explains that Nebulon is going to destroy half the Earth, and then use mind-control on the Avengers to rule what's left. Cap steps forward to talk, but his move is taken by Surfer to be aggressive and he fires a warning burst of cosmic energy which scatters both teams.
All this is being watched by the female from an orbiting spacecraft, weeping.
We now flash back to earlier that morning at Defenders HQ. Valkyrie flies in on her winged horse Aragorn. She's just returned from Asgard where Brunnhilde's spirit was reunited with her Asgardian body (Def#108-109), and so she's much bigger and stronger than she used to be. The only other Defenders present are Beast and Gargoyle, with Wong visiting from the Sanctum.
The reunion is disrupted by the teleporting arrival of the female Nebulon, who calls herself Supernalia. She claims to be a bounty hunter from Nebulon's world come to capture the alien villain. She says that he is going to destroy half the world with 4 antimatter bombs. But he's hiding among the Avengers whom he has under mind-control, and he's going to use them to rule the survivors.
Beast is suspicious and wants to ring his Avenging ex-buddies. But Supernalia makes him believe he has already contacted them and they brushed him off. Wong adds that Nebulon attacked him at Strange's house, but he stangely can't remember the conclusion of the incident. The team take this as evidence of the alien's mental tampering (but of course they're blaming the wrong alien).
Beast mentions that Dr Strange is off searching the dimensions for the missing Daimon Hellstrom and Sub-Mariner (#109 again), so they'll need help to tackle the Avengers. Valkyrie thinks of Silver Surfer, and Supernalia teleports him there. The 4 heroes agree to fight Nebulon and the Avengers. (Presumably Supernalia teleports them to the Mansion, with Surfer's board but without Aragorn.)
Now we're back at the confrontation in Avengers Mansion. Brunnhilde tries to get through to Thor using their past relationship. But she can't convince him he's being controlled by Nebulon. (You'd think his recent experience with Moondragon in #219-220 would at least leave him open to the idea.)
Nebulon decides to attack the Defenders himself. Wasp wants to avoid a fight so she asks Iron Man for a diversion. He blasts a hole in the roof and the Avengers and Nebulon retreat through it. Cap and Thor are sure the other team aren't behaving like themselves. So Nebulon teleports them all to the Himalayas. But Supernalia ports the Defenders after them.
Nebulon restarts the fight. But when Silver Surfer mentions Supernalia he falters at that name. Until he's silenced by a blast of bio-mystic force from Gargoyle. Cap realises that this Supernalia must be what's making the Defenders so aggressive, but Valkyrie won't be swayed.
Now the 2 teams really fight:- Beast vs Cap, Gargoyle vs Wasp, Surfer vs IM, Valkyrie vs Thor. Up in space Supernalia detects Brunnhilde starting to wonder if Thor is right. So she decides to give Valkyrie an advantage by sending Aragorn to her side. Cap and Beast are well-matched. Iron Man is struggling against the cosmic power of the Surfer of the Spaceways, even though his foe is automatically holding back. Wasp is sowing seeds of doubt in the mind of the inherently peaceful Gargoyle.
Thor blasts Valkyrie and Aragorn with lightning, separating them. But this only angers Brunnhilde more, so she hits him a stunning blow when he plucks her from the air. She drops back onto her steed as Silver Surfer sends the Thunder God plummeting to the ground. Shellhead uses his hip pods to siphon off some of Surfer's energy, then absorbs more in his armour as SS attacks and fires it back at him. The resulting explosion leaves them both unconscious.
Gargoyle miscalculates his mystic blast and Wasp falls. As he instinctively goes to her aid she summons her last reserves to sting him. His last awake thought is to wonder why he's so weak that such a thing affected him. Cap and ex-Avenger Beast are both concerned for Jan. But this only momentarily stops their fight. Until Steve Rogers suddenly stops fighting and lets Beast keep hitting him. This shocks Hank McCoy to his senses.
Nebulon has been awake for a while, and has been causing both sides to feel progressively weaker. Now he challenges Supernalia to face him. She ports down from her ship and he greets her as his wife. It turns out his choice of exile over suicide has brought disgrace to their family. And she came to Earth to kill him. But when he teamed up with the Avengers she needed to recruit the Defenders to her side.
Beast and Cap are the only Earth warriors awake, and Hank no longer believes Supernalia. But she proves that her husband was also deceitful. She uncloaks a device Nebulon had hidden here, which has been sapping their powers and wills. She says he intends to use that energy to regain his own full power, and then rule the world as she had predicted. And Nebulon admits it.
Weakened Beast and Cap are easily brushed aside. Now Supernalia quotes her race's non-interference rule, until Henry McCoy points out she's been interfering all along. However the realisation only makes her choose honourable suicide - but her husband stops her using her gun (which she pulls out of nowhere) on herself.
Cap summons up his last reserves to throw his shield, redirecting the ennui-ray from the Avengers/Defenders to Nebulon. The teams start to revive, but Beast realises that the beam is killing the alien. He tries to move the ray again but Supernalia stops him, and throws herself into the beam with her husband. The machine overloads, but the aliens revert to their monstrous real forms and die.