As Sinestro informs Hal on what had happened to the planet Krugar, Hal reveals what he has learned of Brainiac sapping the Sinestro corps' energy and recommends attacking the conqueror directly.
Realizing that Brainiac might be too powerful for the Green Lantern Corps to handle on its own, Hal joins Sinestro in the attack, however, as Brainiac reveals that he is just a hologram, Brainiac abducts the Sinestro Corps' Central Power Battery; robbing the corpsmen of their powers. While Hal attempts to generate an atmosphere bubble to keep the remaining corpsmen in space alive, he is assailed by Brainiac's machines in spite of Sinestro's best efforts and his arm is broken.
Awaking after the battle and Brainiac's escape from the Green Lantern blockade around the planet, Hal learns that Sinestro and his corpsmen are dead.
"I'm not sure you're on the right side of this containment field." — John Stewart to Guy Gardner