Picking right up where the previous story left off, The Ultimate Foe opens up with the Doctor being accused of genocide. The Doctor objects, and both he and the Valeyard get into a well-written argument that suddenly ends when Sabalom Glitz and future companion Melanie show up almost literally out of nowhere. When the Doctor asks how they got there, the Master shows up to torment the Doctor and everyone else - revealing major plot points like how Ravalox (from the first part) was really the Earth. Furthering his gloating, the Master reveals that the Valeyard is really the Doctor. Oh. Shit.