World's Best Comics: Silver Age Sampler #[nn]

Synopsis

Dictator Xandor banishes Carthan to Earth, and, to ensure he stays there, also sends three machines. If Carthan attempts to leave Earth without removing their coverings, he will go blind; he can leave with his sight if he removes the coverings first, but that will destroy the planet. Carthan challenges the JLA, now including Green Arrow, to disable the machines. After disabling the machines, the JLA enters Carthan’s ship, where he imprisons them in a hollow diamond until he can explain. When Carthan is unable to release the JLA, Green Arrow finds the diamond’s weak spot and shatters it.