While concerned about the movements of the "Seven Old Men," Sakuya and Lilithea accept a request to find a ring.They head to Mizushima Park, the amusement park where the ring is believed to have been lost, and as they search the park, they receive a call from Fido, Britain's top detective.They try to meet up, but Sakuya is involved in a car accident and they miss each other.After being taken to the hospital, Sakuya contacts Lilithea and tries to return to Mizushima Park. On the way, a major incident occurs on the Ferris wheel…

Sakuya and his team investigate a brutal murder that occurred on the Ferris wheel at Mizushimaen.How could someone kill 16 people in 15 sealed gondolas while the Ferris wheel completes one rotation?A boy stabbed in the back with a knife. A middle-aged couple injected with poison. While the causes of death vary, the victims share a common thread…Sakuya, cross-referencing the information he received under Fido's instructions, begins to uncover the full picture of the crime. Who is the real culprit…?

Sakuya and his group are heading to Reginleif, an island owned by Shardina.However, their ship starts to take on water along the way. Sakuya is thrown into the sea from the sinking ship.When he wakes up, he finds himself washed ashore on a small island called Aquario.After confirming that Yuri and the others are safe with Lilithea, who has come to meet him, Sakuya joins them at a mansion built on the island.They are warmly welcomed by the mansion's owner, Luciola, and the waiter/tutor, Ursuna, and the group deepens their friendships.Meanwhile, a photographer named Harvey shows up at the mansion and begins to act suspiciously...