While the four leads of this story have absolutely nothing to do with each other, they're all compelling and interesting characters, and so I was intrigued to see them interact. The story seems positively averse to doing so. Nine, The Unbound Doctor, The Lumiat and Liv don't get much of a chance to bounce off of each other, and their lack of actual interaction is perplexing. They're mostly running away from things, and none of them get any chance to say what they think of events. Speaking of events, the plot is barebones and involves the characters solving riddles and prophecies to open doors in the tomb of the Time Lord Immemorial. It's like a sequence in a video game where you have to open all four doors to complete a level. Once again, I'm just genuinely perplexed as to how this turned out this way. All four of these characters are deep and interesting. They could have done literally anything else here and I'd probably have given it an 8/10. What is happening.