There is not just one you, there are many yous. We're part of a multiplicity of universes in parallel dimensions - and Tejendra Singh has found a way in. But he's been kidnapped, and now it is as though Tejendra never existed. Yet there is one clue for his son, Everett, to follow: a mysterious app, the Infundibulum. The app is a map, not just to the Ten Known Worlds, but to the entire multiverse - and there are those who want to get their hands on it very badly. If Everett's going to keep it safe and rescue his father, he's going to need friends: like Captain Anastasia Sixsmyth, her adopted daughter, Sen, and the crew of the airship Everness.