A mysterious explosion has ignited in the Eurotunnel in Britain. So far, the thoughts are that France bombed the tunnel as part of their retaliation during World War 3. However, Necessarius believes differently, and has called in Index to investigate.
Meanwhile, Ben, Mikoto, and company, have spent the better part of the entire year battling on the side of Academy City in various warzones, Ben further questioning all the while whether the side he picked is the right one. So far, the only reason for the war not breaking out into something worse is due to Russians fearing the power of Ben's current most powerful form: Atomix.
However, Ben and Mikoto are called by Necessarius to accompany Index and Touma as an extra security measure to investigate the Eurotunnel Bombing. And along the way, Ben meets the 3 Princesses of the British Royal Family, Rimea, Villian and Carissa.
Villian is currently being backed by Necessarius for the throne.. however, Carissa is intent to gain her royal birthright.. by any means necessary.