The party finds Yuna at the capital city of Bevelle where she is in a wedding gown to be joined with Seymour. Tidus and his group crash the wedding and force their way through, and Yuna tries to send Seymour. Grand Maester Mika stops her, and Tidus and co. are held at gunpoint by warrior monks and Wen Kinoc. After the ceremony Yuna threatens to dive off the tower if Seymour won’t release her guardians. She lets herself fall off the tower, but in midair summons Valefor and is safely taken to the Cloister of Trials.
Rikku throws a flash bomb to distract the guards, allowing Yuna’s guardians to escape. Along the way to Bevelle’s Chamber of the Fayth they discover several machina inside; Auron confirms that this is the “true face of Yevon: they betray their own teachings.” Upon arriving at the Chamber Yuna gains the aeon Bahamut, but the group is arrested. Yuna and her guardians are put on trial by the Maesters of Yevon, where they press their case, claiming Seymour should be sent to the Farplane. Grand Maester Mika reveals he is also an unsent and it seems they are without allies except for the Ronso Maester, Kelk Ronso, who leaves Yevon troubled by Jyscal’s murder.
While imprisoned Auron tells Tidus about the “spiral of death” that traps Spira: the summoners sacrifice themselves to defeat Sin, but Sin will always return. Yuna and her guardians are deemed traitors and sentenced to the Via Purifico, a dungeon said to be inescapable. At the exit, Yuna is confronted by Isaaru, who places his loyalty to Yevon above his friendship to Yuna. The two duel with their aeons and Isaaru is soundly beaten. Making their way to Bevelle’s exit, the party finds Seymour with Kinoc’s corpse. Seymour reveals his true plan is to “save” Spira from its cycle of death by becoming Sin and destroying all life. Seymour transforms into Seymour Natus, but is defeated.