Season 4 Of Smallville

Apparently, Lex's incredible metahuman immune system saved him from dying, but still, he required blood filtration every 72 hours to flush out the toxins. With his father in jail, Lex decided to continue one of his father's projects: search for the Kryptonian Stones of Power. It was only his discovery of the Crystal of Fire that completely healed him, so that he would not have to depend on blood filtration to save his life.

Lex asked Clark for a second chance, and they reestablished their friendship. Later, he bought a manuscript that contained a hidden map that led to one of the Stones of Power, and also discovered that a family friend, Genevieve Teague, had been searching for the stones and a witch, Countess Margaret Isobel Thoreaux, who happened to be an ancestor of Lana Lang, was also searching for them.

When conducting an experiment on meteor rock, the mineral turned black, which split Lex into two beings, one good and one evil. The evil Lex imprisoned the good Lex in the wine cellar of the Luthor Mansion and began his rampage by trying to kill Clark and Chloe, tempting a reformed Lionel to return to his old ruthless ways, threatening Lana to move in with him, and force Clark to use his powers to bring the world to its knees. Fortunately, Clark was able to use black kryptonite to recombine Lex and Alexander. It is still unclear as to what would have really happened if either the good or the evil Lex had been killed. As stated by the evil Lex, he was concerned as to what would really happen if something were to happen to himself or Lex.

After learning that Lana and Lionel each had a stone, Lex tried to get ahold of them, but they were both eventually taken by Clark. Angered, even when he found his office a mess with Chloe there, he figured that Clark was in the mix of all it. Incredibly obsessed and notwithstanding the impending meteor shower, Lex dragged Chloe along with him to the Kawatche Caves to find Clark, but was knocked unconscious by Chloe.