As the conflict between Metatron and Castiel grows, Castiel begins to realize that he has a spy amongst his ranks. Wishing to even out the odds, Castiel decides to contact Gadreel, Metatron's second in command to act as his own spy after talking to Sam Winchester to learn about Sam's impression of the angel.
Gadreel agrees to meet with Castiel in a forest clearing and comes alone while Castiel is accompanied by a single guard. Metatron has Gadreel followed and after learning that Gadreel is meeting with Castiel, sends a pair of assassins to kill Castiel. Metatron would later claim that he left strict instructions with the assassins not to harm Gadreel.
As Castiel's Guard takes on the male assassin, Castiel draws his angel blade and takes on the female. Castiel is quickly able to knock the female assassin to the ground and kill her with his angel blade to her chest.
In the meantime, Castiel's Guard and the male assassin fight it out, with the male angel throwing the guard to the ground at one point. Though the guard puts up a valiant fight, she proves to be no match for him and is quickly killed.
Moments after Castiel kills the female assasain, the male charges him. Castiel blocks the assassin's attack and kills him with his angel blade to the assassin's gut.
The following day, Gadreel meets with Castiel once more to insist upon his innocence in the assassination attempt. While Castiel believes Gadreel, he uses the incident as proof that Gadreel is fighting on the wrong side. Castiel points out that Gadreel met with him in good faith, but Metatron used Gadreel to attempt to kill Castiel with concealed assassins. Castiel requests that Gadreel act as his spy against Metatron to even out the odds and leaves him considering the situation.
Gadreel later confronts Metatron about the attack. Metatron insists that he saw his chance to kill Castiel and he took it with Operation: Lee Harvey. However, Metatron states that he left strict instructions that Gadreel was to be unharmed. Metatron's actions in using Gadreel in such a way begin to shake his faith in Metatron as he begins to realize that Castiel was right. After Metatron's Suicide Bombings, Gadreel's faith is broken completely and he defects to Castiel's side.
- Lee Harvey presumably refers to Lee Harvey Oswald, the man who assassinated President John F. Kennedy.
- The attack is called Operation: Lee Harvey by Metatron in Stairway to Heaven while discussing the event with Gadreel.
- When arguing with Metatron about the attack, Gadreel states that Castiel's angels stopped it and saved both of their lives. However, Castiel alone fended off the attack and killed the angelic assassins.