Side story of Kyoukai Senjou no Horizon bundled with the first press release of the 1st, 3rd, 5th and 7th Blu-ray volumes of both seasons of anime. This side story follows Asama, Kimi and Mitotsudaira aboard Musashi one year before the beginning of the main story, as Asama is considering to create a music band together with her two friends for the next festival in Aki, a territory under the governance of K.P.A. Italia.
- Volume 1A, Characters
- Volume 1A, Opening
- Volume 1A, Prologue: The Three Girls of the Asama Shrine
- Volume 1A, 1: High Altitude Performer
- Volume 1A, 2: Chicks at Home
- Volume 1A, Afterword
- Volume 1A, Setting
- Volume 1B, Characters
- Volume 1B, 3: Hasty Ones of the Passing Shadows
- Volume 1B, 4: Hidden Ones at a Place of Passage
- Volume 1B, 5: Socializer at a Place of Learning
- Volume 1B, 6: Revealed Ones at a Place of Passage
- Volume 1B, 7: Sweethearts at a Place of Wishes
- Volume 1B, 8: Singer Atop the Box
- Volume 1B, Afterword
- Volume 2A, Characters
- Volume 2A, 9: Those who Look Back from Above and Below
- Volume 2A, 10: Girl Soaking in the Tub
- Volume 2A, 11: Girl Being Peeped On in a First Place
- Volume 2A, 12: Measurer of Rank
- Volume 2A, 13: Curfew Girls on an Outing
- Volume 2A, 14: Position-Taker atop a Rectangle
- Volume 2A, 15: Intruder on the Hunting Ground
- Volume 2A, Afterword
- Volume 2B, Characters
- Volume 2B, 16: Viewer in the Sky
- Volume 2B, 17: Experienced One on the Enemy
- Volume 2B, 18: Doll Looking Back to a Nostalgic Place
- Volume 2B, 19: Speakers on an Angled Surface
- Volume 2B, 20: Respecter in a Warm Place
- Volume 2B, 21: Helper in a Miniature Garden
- Volume 2B, 22: Namers of a Decisive Place
- Volume 2B, Last : You and a Cage while Waiting for Morning
- Volume 2B, Afterword
- Volume 3A, Characters
- Volume 3A, Prologue: Drunk Girl at a Place of Washing Away Impurity
- Volume 3A, 1: Noisy Girls by the Window
- Volume 3A, 2: Insufficient One at a Half Place
- Volume 3A, 3: Those with Too Much in the Measuring Room
- Volume 3A, 4: Deliberators Before the Darkness
- Volume 3A, Afterword
- Volume 3B, Characters
- Volume 3B, 5: Evictors in a Place of Accumulation
- Volume 3B, 6: Visitor on the Open Surface
- Volume 3B, 7: Reporter in an Official Place
- Volume 3B, 8: Winged Ones Standing Up
- Volume 3B, 9: Player at the Shrine
- Volume 3B, 10: Thinking Girl Standing Up Once More
- Volume 3B, 11: Visitor at an Inspection Point
- Volume 3B, 12: Responders of the Twin Walls
- Volume 3B, Final : Those who Look Up at the Normal World
- Volume 3B, Afterword
- Volume 4A, Characters
- Volume 4A, 1: Novice Girls in the Study Room
- Volume 4A, 2: Panicked One in the Testing Room
- Volume 4A, 3: Gift Giver in the Shrine Bar
- Volume 4A, 4: Dancers Waiting for Night
- Volume 4A, 5: Warner on the Horizontalt
- Volume 4A, 6: Blossoming Girls in an Enclosed Place
- Volume 4A, 7: Beginners in a Sleepy Place
- Volume 4A, Afterword
- Volume 4B, Characters
- Volume 4B, 8: Expert in a Hidden Place
- Volume 4B, 9: Deceiver Before the Stage
- Volume 4B, 10: Defenseless Girl in a Place of Skin Contact
- Volume 4B, 11: Wolf in the Reverberation
- Volume 4B, 12: Bargaining Girl in the Lead
- Volume 4B, 13: Hopers in Connected Rooms
- Volume 4B, 14: Decorators in a Closed Place
- Volume 4B, 15: Surprise Stage Performer
- Volume 4B, 16: Creation of an Unrivaled Field
- Volume 4B, 17: Destroyer on Stage
- Volume 4B, 18: Endorser of the Usual Garden
- Volume 4B, 19: Gifter at a Promised Place
- Volume 4B, Final : Musashi’s Songstresses
- Volume 4B, Afterword