The Ultimate Vampire Resource and Directory

In the second book of the Upside Down series, Ayaka, Millicent, and the rest of the team return to Tilt in order to save their comrades, but things don't go as planned. A new menace, the Resurgence, are hot on their heals, and the team has to move quickly to save themselves. The artificial intelligences they developed are also in danger, but saving them may risk the rest of the team. When the Resurgence attacks, they target only the AI's, complicating the whole situation. If you love classic SciFi like Asimov, Banks, Reynolds, or Heinlein you will love the Upside Down series.