Lex is desperate to answer questions that have eluded him ever since the town of Smallville became part of his life seven years ago. He knows that the answer to these questions is within his grasp if he can get hold of a key that he believes to be around the neck of his own father. Feeling insulted and unloved by his father over the years, the final straw is drawn when Lex realizes that much of his own life was sacrificed for the future of this Traveler. After making a climactic decision, the good in him begs to not search out the secrets that may be in Zurich. Meanwhile, Clark learns the atrocity that Lex committed and the tragedy which he has brought to others, understanding that he and his former best friend have become mortal enemies.
Every scene in 'Descent' is dynamite, from the final Lex-Lionel confrontation at LuthorCorp to the first full-fledged meeting of animosity at the Luthor mansion that now pits the true antagonist and protagonist of the show. These scenes had so much impact involved due to superb acting and an element of the story that has been foreseen since the show's early years. 'Descent' is perhaps the darkest, and one of the most emotionally impactful episodes of the series.