Logan explores the underground world of Rome. Because of this, he is targeted by criminals and escapes with the help of Penelope. Later, they are constantly followed by mysterious people and attacked by black-clad men. After being cornered in an abandoned warehouse, they escape into a church. There, they meet an old man who tells them that the diary is the key to finding the entrance to the underground world. The team follows the clues in the church frescoes and enters the underground passageway, where they encounter various dangers, including monsters!