天使 season 4, episode 10: Awakening 

Full episode 10 from season 4. Cordelia has a vision, which reveals that the Beast once knew Angelus. Since 天使 has no memory of this, the gang realizes that there is only one thing to do. They must find a way to bring forth Angelus.
密码: 天使, season 4, full episode, episode 10, awakening