Banner, Betty Ross, Skaar, Korg, Lyra, Jen Walters, and A-Bomb (Rick Jones) had hidden themselves out on a beach in Dry Tortugas, Florida, even though national media had recognized them as the heroes of the AIMarines disaster in Washington D.C. Bruce approached Betty, trying to rekindle their estranged relationship, but only succeeded in angering her - causing her to transform into the Red She-Hulk. Immediately, she jumped several miles away, causing a good deal of destruction and alerting the authorities as to their whereabouts. After a short scuffle, Banner transformed into the Hulk and chased off after Betty. The two fought for a brief time, leaving Skaar in the care of Korg and A-Bomb. Skaar began to sense something amiss (at the exact same time as Amadeus Cho, Reed Richards, Tony Stark and Beast), and informed Korg and A-Bomb that he must find his father. They told him to leave 'mommy and daddy' alone while they fought, but Skaar was insistent, and quite upset.
Hulk continued to battle Red She-Hulk, trying to calm her down so he could talk to her, but she believed that it was Bruce, still trying to talk to Betty. Hulk told her that he only wanted her to stop causing so much damage because it put his son, Skaar, in danger by drawing attention. Hulk was convinced that Skaar was changed and didn't want him to grow to be like he and the other 'angry' Hulks. As the two continued to brawl, a wave caught Skaar (who had remained in his puny form since his fight with Hulk), but he was saved by Red She-Hulk. At this moment Steve Rogers and Amadeus Cho appeared behind Hulk, informing him that they needed to talk. Hulk tried to push Rogers away, but Rogers and Cho were only projections. They informed him that the planet K'ai ( Jarella's world) had just appeared on the edge of the solar system and that Rogers had only been given a 48-hour window to intervene before the government's intercept-fleet did. Hulk distrusted the idea of anyone shipping him anywhere in a space ship, for obvious reasons, but it was the pleading of Skaar that convinced Hulk to decline. He promptly smashed the ship that Rogers brought along. Hulk asked Skaar what he had to say, and Skaar whispered into his ear the truth: the second Son of Hulk was on his way to earth.
As Rogers and his Secret Avengers prepared to launch their fleet of interception crafts toward the incoming planet K'ai, the Hulk showed up and began destroying the fleet. The Secret Avengers opened up on Hulk and seemingly disabled him. As War Machine began to place some rather enormous cuffs on him, Hulk revealed that he was only leading them on, and the rest of the Hulks (She-Hulk, Red She-Hulk, A-Bomb, Skaar, and Korg) burst from the ground. Earlier that day, Hulk had Skaar training and focusing his Old-Power in an attempt to get a read on Hiro-Kala's position in the skies. As the other members of the Hulk family distracted the Secret Avengers, Skaar made his way to a 'repair bay'. Seeing him as no threat, Rogers let him go. Hulk powered down, telling Rogers and his team that he had just saved all their lives and the lives of a hundred other astronauts on their way to intercept his son. Bruce told Steve that if he went up there, Hiro-Kala would kill him. Or that Rogers would be forced to kill Hiro-Kala, then the Hulk would have to kill Rogers.
During this time Skaar had been repowering the Sakaarian Stone Flagship that Hulk and his Warbound had brought to Earth to wage war on its heroes. The Flagship rose from the hangar and the Hulks escaped into space, headed toward the incoming planet K'ai. Upon nearing K'ai the group noticed that the planet itself was surrounded by spacecraft that seemed to be towing the planet. After scanning the ships and seeing no brain activity from within, the group was sent out to destroy the ships, with the assumption that it would cease the progress of the planet. As the group began cutting into the ships they began to notice that they were piloted after all. Just as this realization was hit, so was the Sakaarian ship... rammed by one of the K'ai starships. Even with the destruction of those that seemed to be towing the planet, K'ai was still moving. Banner sent the
crew to the planet to find the source of the power that was causing it to move and smash it. Skaar insisted on going with Banner to confront (destroy) Hiro-Kala, but Banner transported Korg, Skaar and A-Bomb to a different part of the planet while he transported directly to Hiro-Kala's position. Bruce was immediately attacked by the mindless, controlled population of K'ai and had no resort but to defend himself, apologizing the entire time. After the initial wave was taken out, possessed children began to attack him. Blinding them with an explosive, Banner retreated, only to be attacked by Hiro-Kala himself. Hiro-Kala slaughtered the children with an energy blast, and the blast depleted Banner's Banner-tech shields as well. After asking Banner who he was, Banner replied that he was his father, and promptly powered up into the Hulk, calling Hiro-Kala a 'little monster'.
Hulk asked Hiro-Kala if he knew that in attacking the Hulk, he would kill the mind-controlled children, and Hiro-Kala responded, "Of course", and proceeded to kill several more with a blast of power. This enraged the Hulk and he attacked his son. The two fought back and forth while Hulk argued with Skaar (via an earpiece). Skaar didn't believe that Hulk would be able to kill Hiro-Kala and that since he was the 'Killer of Killers', he should come take care of the job. During this time, Skaar, Korg, and A-Bomb were supposed to be redirecting the blast of K'ai's volcanoes to redirect their course away from Earth. Skaar absorbed the force of the explosion to avoid killing innocent people and apparently sacrificed himself. During this time, Hulk had gotten the upper-hand on Hiro-Kala and had come to realize that he couldn't kill his own son. He then reverted to Banner, and Banner zapped him with an
Old Power taser. In doing this, he caused Hiro-Kala to lose control of his Old Power and at the same time, Skaar reappeared behind them, sword in hand. Immediately before the fight, Banner grabbed the only two surviving K'iatian children and teleported to the location of the She-Hulks, who were trying to stop the mindless masses from dying. The Woldmind could only revert the mindless people that it could physically touch, due to the damage done by Hiro-Kala. Banner rigged up a modification to his Bannertech teleportation system and powered the Worldmind's signal to revert everyone else across the planet. At this time, Betty, in her human form, seemed to be falling for Bruce again, dropping some of the doubt she seemed to have while they were in Florida.
The two fought briefly and Skaar easily overpowered Hiro-Kala. Skaar grabbed him and began to try to talk him down, showing him some of his memories, via the Old Power, of Caiera and how he came to be banished to Earth. He told Hiro-Kala that Banner had helped calm the monster within him and that Bruce could do the same for him. At that moment, Banner returned, and Hiro-Kala began to show them some of his own memories, hoping that these would show the two why he had to destroy the Old Power. He searched for the memory wherein Caiera told him to destroy the Old Power, but he could not manifest it. The K'ai Worldmind informed him that it was not a real memory and the Old Power could not manifest dreams. At this, Hiro-Kala erupted in anger, blasting Banner away from him. At this moment, Skaar grabbed Hiro-Kala and fused him into the stone surface of K'ai, immobilizing him. Believing that he was now calm enough to transport to Earth, Banner told Skaar to free him, but as Skaar tried to use the Old Power to release him, he could not. The K'ai Worldmind would not allow it. The Worldmind lifted the stone mound from the ground and used Hiro-Kala's power to heal the planet. Hiro-Kala's last words to his father were: "You tried, father. But the Worldmind is right. Your can't ever make this right. You were too late."
The Hulks left the planet, but not before Axeman Bone asked Skaar to remain there and be their hero. Skaar declined, telling him that they were fresh out of heroes. Aboard the ship, Banner had again become the Hulk, and as Betty Ross tried to comfort and congratulate him, Hulk yelled at her in his anger over losing his son. At this, Betty transformed back into her Red She-Hulk persona while Korg tried to tell the group that they needed to prove to Hulk that they would always be there for him, regardless of what blame he tried to put on himself. Red She-Hulk scoffed at the idea, telling them that they needed to realize that some people are meant to be alone