In the Emperor's absence, Sophia orders the Urbanus to stop General Vitellius from attacking Disith in compliance with a ceasefire. The arrival of Duke Mad-thane's fleet forces Disith to withdraw. The following day, a vanship courier arrives with a message from Walker, who invites the Silvana to Horizon Cave for repairs and resupply. Lescius reveals himself as a member of the purged House Dagobert and entrusts Alex with the third Mysterion. Prime Minister Marius, a member of the purged House Bassianus, also sent the final Mysterion to Alex before his death. The Silvana finally arrives at Horizon Cave, currently used as a training base for an assault against the Guild. Although the Guild suspects of a rebellion, Delphine decides not to take immediate action. At the base, Claus meets Mikhail Wednesday, elder brother to the late Ralph Wednesday from whom Claus took over the duty of delivering Alvis. Claus and Lavie are also reunited with fellow vanship pilots from Norkia after Duke Mad-thane, who was inspired by Claus's and Lavie's actions at Minagith, called for all pilots to fly as fighter support.

When Claus and Dio return to the Silvana, the crew is missing. When they go to search the bridge, they find that Delphine has captured Alvis and the ship. Tatiana and Alister sneak a transport carrying Sophia back to the Urbanus. Alex comes out of hiding to attack Delphine but is defeated by Cicada. Delphine takes Dio back to the Guild along with Claus, Alvis, and Alex, and orders that Exile be secured before they leave. On the Urbanus, Vincent promises Sophia that he will recapture the Silvana. When they return to the Guild, Dio is taken to prepare for the Rite of the Covenant. Delphine indulges in the world's rarest delicacies at dinner, causing Claus to become upset about her disregard of the hardships of the people of Anatoray and Disith. Dio is reunited with Claus and Alvis, but they find that his personality has changed and he no longer recognizes them as friends.

A portion of the Guild fortress breaks apart and falls away from the Grand Stream into Anatoray. Claus escapes in the vanship that was brought with them to the Guild stronghold and takes Alvis and Dio to Norkia. Dio is then left in the care of the Mad-thane residence, which has been converted into a makeshift hospital. Claus takes Alvis back to his wrecked house, where they stay overnight. The combined Anatoray and Disith alliance fleet launches a surprise attack on the Guild fleet and, helped by the vanship squadrons, emerges victorious. It continues to pursue the withdrawing Guild ships into the Grand Stream. When Claus and Alvis are finally able to contact Lavie and the Silvana with Lucciola's communicator, they are told to make a rendezvous at the Dragon's Fangs.