the Process in its Watch Tower. The Process sends Vael to investigate. When Vael and the Process’s insect-like guards arrive, the Phazels help Ace to escape. She and Shonnzi get away and discover a ghost-like image of the Doctor. Believing him to be dead, Ace begins to grieve. But Shonnzi tells her that he has been given many of the Doctor’s memories. Ace and Shonnzi are forced to split up as they are discovered by the guards. Vael manages to capture Shonnzi and take him back to the Process, but Ace escapes across a mercury river. Across the river, Ace realizes that she is in the same place she was before, but at an earlier time. She witnesses the arrival of the Chronauts and the death of the Doctor at the hands of the Process. Believing that she and the Doctor are to blame for their predicament, the Chronauts turn on Ace and hand her over to the Process. Vael betrays his fellow Chronauts, who are enslaved by the Process and sent to search for the Future stolen by the Doctor. Vael drags Ace back to the Watch Tower, where the Younger Process prepares to eliminate her. But it is interrupted by the arrival of the Older Process, who has come to discover why the past is no longer as it remembers. The Doctor’s ghost appears, which allows Ace to escape. She comes across a silver cat that leads her to the top of the Watch Tower. There, Ace discovers that the World exists on the inner surface of a hollow sphere, and there are three different Cities existing at three discrete moments in time stretching out from the Watch Tower. She also finds Shonnzi imprisoned in a cocoon and releases him. As Vael chases them, the cat trips Ace, causing her to fall from the top of the Watch Tower. She is caught by some sort of force field and begins to slowly descend toward the ground. Shonnzi jumps after her and is also protected. Ace concludes that the TARDIS must still exist, somewhere, and must be protecting them. Back on Gallifrey, the Pythia's prophetic powers suddenly desert her, and she becomes fanatically obsessed with locating her male successor, who she believes to be Vael. In reality, her promised successor his Rassilon. The TARDIS key glows in Ace’s hand and leads her to an old attic that she recognizes