The Guardians of the Galaxy watch over the newly resurrected and imprisoned Thanos, while debating whether they should kill him and how his death might impact the universe. Meanwhile, Nova pursues the false Quasar — who originated from The Fault and briefly took over Project P.E.G.A.S.U.S. on Earth — into deep space as he broadcasts warnings about the danger The Fault represents. The real Quasar responds, telling him that an armada of Kree/Shi'ar ships is on its way to The Fault. As Quasar takes off to help capture his impostor, Nova intercepts the false Quasar at the mouth of The Fault, where he discovers numerous fleets of ships belonging to the Universal Church of Truth lying in wait. Nova is suddenly attacked by Adam Magus, but is assisted by Quasar, who quickly dispatches his other self. To Quasar's surprise, numerous planets belonging to The Universal Church of Truth suddenly teleport next to The Fault. Magus brushes aside both Nova and Quasar and chants one word: Ignition. The planets suddenly detonate, resulting in a massive cosmic-scale explosion that rips open The Fault. Mantis, Moondragon and Cosmo sense that something "very bad" has just happened, but before the Guardians of the Galaxy can react, Thanos breaks free from his cell and begins running rampant. Meanwhile, a mysterious figure from The Fault approaches Magus and the false Quasar. They acknowledge him as their lord and report their progress to him. As the shadowed figure seemingly kills Magus, he is revealed to be an alternate version of Mar-Vell, who declares that his first priority will be to cleanse this universe of death.
As Nova and Quasar struggle to defend the Kree/Shiar warships against the creatures of The Fault, they receive assistance from the Silver Surfer, who heralds the arrival of Galactus, Aegis, Tenebrous, and the Celestials to the battle. On the other side of The Fault, the Guardians of the Galaxy easily dispose of the alternate Defenders, before realizing that their foes cannot die in the Cancerverse. The Defenders begin to hesitate in fear of Thanos, who regains consciousness and obliterates the Defenders, discovering that he alone can deliver permanent death to beings in the Cancerverse. Thanos and the Guardians are approached by the alternate version of the Vision, who is unchanged due to his inorganic nature. Meanwhile, as Nova, Quasar and the Silver Surfer watch Galactus and the other cosmic abstracts, they observe something huge coming from The Fault. The Surfer tells them the enemy is responding to the arrival of Galactus and the other abstracts, and describes the approaching object as "a blasphemy, a heresy.... The Galactus Engine." A massive mechanical Galactus-shaped head then emerges from The Fault, dwarfing even a Celestial in size as it approaches. During the invasion of the Cancerverse into mainstream Marvel reality, the Guardians of the Galaxy and a newly-resurrected Thanos were forced in turn to go into the Cancerverse to effect a means of saving the Marvel Universe.
However, the mix of metaphysical energies involved in the death-free Cancerverse threw Drax's "anti-Thanos" programming into overdrive (since Drax himself is a so-called 'Avatar of Life'), and even the extreme, universal peril of the situation could not stop the normally sane hero from lashing out at Thanos uncontrollably. Thanos was finally forced to disintegrate Drax with a single, massive blast. The rest of the Guardians of the Galaxy met on Titan to take the fight back to Lord Mar-vell while Nova and his Cosmic Avengers, Beta Ray Bill, Ronan, Silver Surfer and Quasar dealt with the Revengers directly. In the resulting battle, Nova's team was defeated and he channeled a large portion of the Nova Force into Quasar before leaving to take on Mar-vell himself. It was there that Thanos betrayed his team to Lord Mar-vell and the Many Angled Ones but when Mar-vell went to kill Thanos, it was revealed that Death was hiding inside him and that is why he was unable to be killed.
In doing so, Death killed Mar-vell and destroyed the Cancerverse but at a price. Thanos was once again ignored by Death that sent him in a furious rage. With no choice left, Starlord used the last of the cosmic cube power and Nova used the entire Nova Force to send the Guardians of the Galaxy back to the 616-Universe and contained Thanos long enough for the Fault to collapse on itself trapping all three of them in limbo. It us unknown if any of them survived. Rocket and Quasar are left in the aftermath of the war looking over two statues of Nova and Star-lord with Rocket replying: "Dammit guys. Why did you have to be such heroes?"