The day arrives for Accelerator's bandages to come off after he is shot in the head, and Last Order is eager to celebrate. A secret weapon is stolen from an atmospheric research facility, and the culprits seem to be targeting Accelerator with it.

The film adapts and expands the Planetarian visual novel by Key. The story is set in a dystopian future where biological and nuclear warfare has left a once prosperous civilization in complete ruin. The film tells the story of an old man travelling around with a mobile planetarium projector to show people the stars.

The staff at the "Dai-Ni-Kai 'KanColle' Kankanshiki" event in Yokohama in August 2015 announced that the Kantai Collection franchise will get an anime film in 2016. The event screened footage that features the Kan-musume characters Fubuki, Mutsuki, Yuudachi, Akagi and Kaga, Hiryuu Kaini and Souryuu Kaini, the four Kongou sisters (Kaini), Kitakami and Ooi, Choukai Kaini, Yuubari, Mutsu and Nagato, Kako Kaini and Furutaka Kaini, Zuikaku and Shoukaku, Shimakaze, Kuma, and Ouyodo.