There is a gala opening for a new exhibition at the Tate Modern - "The Tomorrow Windows." The concept behind the exhibition is simple - anyone can look through a Tomorrow Window and see into the future. Of course, the future is malleable, and so the future you see will change as you formulate your plans. You can the see the outcome of every potential decision, and then decide on the optimum course of action. According to the press pack, the Tomorrow Windows will bring about world peace and save humanity from every possible disaster. So, of course, someone decides to blow it up. There's always one, isn't there? As the Doctor investigates and unravels the conspiracy, he begins a Gulliver's Travels-esque quest, visiting bizarre worlds and encountering many peculiar and surreal life forms...