
First Stage: The Sekirei are adjusted and released in Tokyo.The second anime season ended with the Second Stage completed, but before the Third Stage matches begin.

The true purpose of the plan is unknown, but it is implied to be sinister to some extent. The Sekirei Plan ( 鶺鴒計画 Sekirei Keikaku), known to Minaka and others as the ' Game', is a competition in which the Sekirei and their Ashikabi must fight for survival until the last one of each remains. If an Ashikabi dies, all Sekirei winged by him or her will also perish. One of them is Natsuo Ichinomi, the leader of the Disciplinary Squad, while each one of the four others control a different area in the city Minato Sahashi from the North, Hayato Mikogami from the South, Izumi Higa from the East, and Nishi Sanada of the West. As the Sekirei fight escalates, five Ashikabi in particular, ascend as the favorites to win the Sekirei Fight, each having winged at least three Sekirei.

In the series, the power of an Ashikabi can be determined not only by the number of Sekirei he or she has in his or her disposal, but by the bond between them. Unlike Sekirei, who are mostly buxom women or handsome young men, Ashikabi can be quite innocuous as they can appear in any gender, age, and even status. Through mucous contact (kissing) between a Sekirei and its Ashikabi, a Sekirei without wings can become a 'winged' Sekirei. Ashikabi ( 葦牙) are humans with unique genes that enable them to empower the Sekirei destined to serve them.
