Smallville :

Lex takes Lionel's locket, which holds the second key to the deposit box in Zürich, and then throws him out the LuthorCorp window to his death. Lex soon discovers the key is not where he thought, and heads to the Daily Planet to find it; he also begins having hallucinations of his younger self.

The day arrives that Clark and Lex became mortal enemies. The secret of Veritas leads Lex in a dangerous direction that will put Clark and Lex in each other's cross-hairs. There is a major power struggle, and one character dies.