Since the beginning of Earth's history, angels from the planet Eden have been carefully monitoring the behavior of its inhabitants, whom they call Earthians. Chihaya and Kagetsuya are two agents sent from Eden to assess the positive and negative aspects of the Earthians' nature. Despite the orders Chihaya was given by his home planet, he frequently ends up entangled in Earthian affairs, much to Kagetsuya's annoyance. Meanwhile, as Chihaya tries to understand the origin of his strange black wings, he uncovers one mystery after another.

In spite of the mayhem that has been taking place in Ikebukuro, Shinra Kishitani and Celty Sturluson have decided to go on a short trip. Excited to finally be going out with the one he loves, the underground doctor makes it his priority to give Celty his undivided attention, even if it means rejecting phone calls from his good friend Izaya Orihara. However, despite his hopes of having a peaceful holiday, Ikebukuro's various residents continue trying to reach him. Furthermore, just as Shinra begins to enjoy reminiscing about old memories on a carriage ride together with his beloved, Celty starts to notice a strange presence...

Music video for the track EDEN by ATOLS from the album MUSIC OF SCIENCE.

One night, Mikado Ryuugamine accepts an invitation to Shinra Kishitani's apartment, eager to talk to Celty as quite some time has passed since the two last spoke. But, much to his astonishment, he finds that a large group of Ikebukuro's finest has gathered there for a hot pot party. Already confused with the current situation, Mikado is further surprised to see that his friend and fellow Raira Academy student Anri Sonohara is there as well. As the two decide to take a seat together, a few members of the group begin reminiscing over events from days past: Mikado recalls an adventure from his childhood with Masaomi Kida, Anri explains how she came to be friends with Mika Harima, and Shizuo Heiwajima tells of his first meeting with Tom Tanaka.