Revelation.It's nearing the end of the year and Jeremy's research has hit a dead end. After the group collects more data from Sector 5, he plans to use a tower to decipher Franz Hopper's diary. Before the mission, Odd gets a message from a mystery girl. When he goes to meet her, he is attacked by one of X.A.N.A.'s ghosts and locked inside a well at the Hermitage. The ghost then assumes Odd's form and goes to Lyoko in his place. The tower that X.A.N.A. activated to make the ghost then deactivates, confusing Jeremy. Putting it out of his mind, he begins his plan to decipher the diary. Shortly after they begin, the ghost turns on the group, devirtualizing Yumi and chasing Ulrich away from the tower as three Tarantulas arrive to protect it. At the same time, X.A.N.A. attempts to take over Jeremy's tower, locking the decoding procedure so they canot abandon it. Jeremy realizes the true nature of the ghost during the fight, and Yumi goes off to find the real Odd. After the ghost proves to be ineffective against Ulrich, it shapeshifts into a clone of Ulrich. In this form, it proves to be an equal match for him. After much fighting, Ulrich finally beats the clone, but is taken out by a Tarantula shortly after. Just when it looks like Jeremy's tower will fall, Franz Hopper steps in and protects it. The diary then decodes fully. After examining the diary, Jeremy tells Aelita that she is Franz Hopper's daughter, much to her shock.