The Dark Flower Withers in the Labyrinth

6 months have passed, and one fine day Thoth suddenly declares that mid-term exams are in 3 days, shocking Yui. They attempt to study together using Tsukito's perfect notes, but a Yui has been experiencing strange dreams of Apollon's past, while Apollon has been losing sleep as well. From the dreams, Yui finds out about a woman named Cassandra that Apollon loved so much to the point where he gave her a part of his divine power to see the future, until she committed suicide much to his anguish. Hades, knowing that Cassandra's spirit never entered the underworld, worries that she holds a grudge against Apollon and is wandering in the human world to haunt him. However, this proves to be the opposite as Cassandra possesses Yui's body to convey her true feelings to Apollon, freeing him from his long-term grief and breaking his shackle, allowing him to graduate. Everyone forgets about their exams until Tsukito reminds them, to which they have done no studying.