Episode 0, consisting of two subepisodes: "Sekirei Shindan" (鶺鴒診断) and "Sekirei Yoka" (鶺鴒余暇), of Sekirei: Pure Engagement included on the first DVD/BD volume.

Returning to the Digital World, Taiki and Shoutmon learn that the Bagra Army has taken it over and reformatted the world to have Seven Kingdoms, each ruled by a general. (Source: AniDB)

Thirteen years after their sudden disappearance, an alien race known as the Heterodyne resurface without warning. To combat the Heterodyne, three office workers from the 21st Century Security Corporation operate Dai-Guard - a giant robot no longer regarded as an oversized paperweight. Unfortunately, Dai-Guard is somewhat obsolete and in disrepair. It's a tough job, but salarymen can also save the world. (Source: ANN)

The story revolves around a rock band formed by a trio of punks, none of whom had prior experience with musical instruments. (Source: MAL News)