Depending on which DC series you are following, "[S4E1] Lex Luthor" refers to two significantly different storylines where the iconic villain takes center stage.
Just as they begin to bond, Lex is violently killed by a supernatural attack orchestrated by Mother Mayhem . He coughs up a large black snake and dies, leading to Conner's arrest for his murder. [S4E1] Lex Luthor
Lex invites Conner to Metropolis, revealing he has only six months to live due to kryptonite poisoning. He asks Conner to take over LexCorp and his legacy. Depending on which DC series you are following,