Kryptonite. Even beyond Superman's colorful world of heroes and villains, the word has become synonymous with our ultimate weaknesses. This glowing green mineral spells certain death for the otherwise indestructible Man of Steel--but it's also the only tangible link he has to his homeworld. But how did Superman discover the one thing that can harm him? In this untold chapter from Superman's earliest days, a suave, savage crime lord makes his move on Metropolis, bringing with him a strange green meteorite from the distant reaches of space. Now everyone from Lois Lane to Lex Luthor to Superman himself is racing to uncover this new villain's secret--not knowing that this seemingly inanimate asteroid has a secret of its own... Eisner Award winners Darwyn Cooke (DC: The New Frontier) and Tim Sale (Batman: The Long Halloween) present a gripping, gorgeous untold tale from Superman's early days--his first encounter with the rock that will rock his world forever! Collects Superman Confidential #1-5 and #11.