Dio and Luciora investigate their downed star-shaped machine. When Luciora fixes the camera on it, they are able to see an image of Alvis being protected by Claus. Tatiana and Alistia arrive at the palace of the emperor and inform him that the "cargo" is safely aboard the Sylvana. And speaking of the cargo, Al explores the ship on her own, making it down to the hangar, where the mechanics entertain her until Sophia retrieves her. Sophia brings her to Claus and Lavi, and later brings the still injured Claus to see Alex. Their talk is interrupted by a red alert claxon. The Guild is about to attack the Sylvana. In the course of the attack, one of the star-shaped machines comes aboard the ship and goes after Alvis. It's destroyed by one of the mechanics, and unfortunately ruins Claus and Lavi's vanship. Claus offers to fly and fight and the mechanics give him a quick review of combat flying. Another star-shaped machine comes on board, and the last scene is Claus, using his vanship, to shov

Following Claus and Lavie aboard the Silvana, Dio and Lucciola allow themselves to be captured. At the Anatoray capital, the Emperor begins to distrust Alex's actions and sends the Urbanus to retrieve Alvis. Alex interrogates Dio, who tries to gain his trust by telling him that the Mysterion passed by House Eraclea. He also reveals that the three Guild houses holding the remaining Mysteria have been purged by Delphine. Vincent Alzey, captain of the Urbanus, requests to meet with Alex. Alex asks Claus to fly escort for his flight to the meeting, to which Tatiana objects. Alister defies Tatiana and offers to be Claus's navigator. Alex informs Vincent that he will not hand over Alvis and will fight to keep her aboard. Dio and Lucciola meet Lescius, the Silvana's chief engineer and a former member of the Guild. Dio then finds Alvis by herself elsewhere and reads her one of the Mysteria, after which she falls into a trance and wreaks havoc on the ship's systems.

Sophia leaves the Silvana to return to the Anatoray capital. When General Vitellius informs the Emperor that Duke Mad-thane has engaged the Disith fleet in Norkia, Prime Minister Marius pleads with him to spare the Disith, who have recently lost their homes. However, the Emperor has already put the Disith envoy to death and places Marius under house arrest. Mullin begins to question why he remains on the Silvana, and reminisces his days as a musketeer. Alex finally considers launching a strike at the Guild, and Claus reveals to Lavie that their vanship belonged to Alex. When Sophia arrives at the capital, she also pleads with the Emperor to set aside differences with Disith and face their challenges together, but he declines and imprisons her in the tower. Sophia is visited by Marius, who raised her after his daughter Euris died in the Grand Stream, and is asked to remain in the tower until after his plans for her to become Empress is completed. That evening, Disith forces make a surprise attack on the Anatoray capital, whose defense fleet is stretched thin. In the confusion, Marius assassinates the Emperor but is fatally wounded himself. As Disith forces enter the capital, Vincent heads to the tower to prevent the Emperor's men from killing Sophia and takes her to safety on board the Urbanus, taking command of the ship again.

The Guild declares war on the new alliance during Sophia coronation ceremony, while the Sylvana heads towards an ambush.

After the Urbanus locates the Silvana and ensures its safety, Sophia returns and is surprised that Claus has been taken. Covenant Day arrives, and Dio takes part in the Trial of Agoon to claim inheritance of the Maestro's position by participating in mortal combat against other Principals. Claus, who cannot bear to see Dio fight, worries that he may die. At the same time, the operation to capture Guild Claudia units commences at Horizon Cave. On the Silvana, Lavie finally completes the repairs of her and Claus's vanship. Delphine takes Alvis and Claus to the location of Exile, where they find its defense system has begun attacking Guild ships as well. Exile attacks Delphine's ship but stops when it senses Alvis's presence. Delphine reveals that Exile is a colony ship used by those who first settled on their world. Alex, who has been injected with a truth serum, recites the Mysteria, and Alvis responds to each one. However, he reveals that he has not read the final Mysterion before entrusting it to Sophia. Delphine then receives word that Dio is the Trial's victor.