"Day 13" episode contains 3 stories focusing on time periods before, during anime's story

Shochiku began streaming a trailer on Sunday for "Day 13," an unaired episode for the 91 Days anime that will be included in the seventh volume of the anime's Blu-ray Disc and DVD home video release in Japan. The video shows a young Nero, Fio, Frate, and Vanno.

The "Day 13" episode will contain three stories. The first story, "Toki no Asase" (Shoals of Time), will center on Nero and Vanno persuading Frate to skip mass with them and see the circus. The second story, "Subete no Kinō" (Yesterday Before Everything), will focus on Ganzo, as he meets a young man named Vincente at a bar, and asks Ganzo to do something for him. The third story, "Ashita, Mata Ashita" (Tomorrow, and then Tomorrow), is set after Nero and Avilio defeat Mad Mack and are on the way back to Lawless. Nero suffers from fever dreams, and Avilio nurses him back to health.

The seventh volume ships in Japan on July 5.

Funimation describes the series as follows:

Prohibition—a time where law holds no power, and the mafia prowls the streets. Avilio Bruno has grown up alone in this murky world after the Vanetti's murdered his family. One day, he receives a letter that holds the key to revenge. Befriending the don's son, Nero, Avilio works his way through the Vanetti family and sets his vengeance in motion. But 91 days of killing can only spawn more tragedy.

The 13-episode series premiered last July, and Crunchyroll streamed it as it aired. Funimation streamed an English dub for the anime last October.

Hiro Kaburaki (Hozuki's Coolheadedness, Kimi ni Todoke - From Me to You, My Little Monster) directed the series at studio Shuka (Durarara!! ×2). Taku Kishimoto (ERASED, Haikyu!!, Magi: Adventure of Sinbad) served as the series script supervisor, Tomohiro Kishi (My Little Monster) designed the characters and served as chief animation director, and Shōgo Kaida (S.A, The Betrayal Knows My Name) produced the music. TK from Ling Tosite Sigure performed the opening theme song "Signal," and ELISA performed the ending theme song "Rain or Shine."