IS: Infinite Stratos Encore - Koi ni Kogareru Rokujuusou
English title: Infinite Stratos Encore: A Sextet Yearning for Love
Japanese title: IS 〈インフィニット・ストラトス〉 アンコール『恋に焦がれる六重奏』
Type: OVA
Episodes: 1
Source: Light novel
Genres: Action, Comedy, Romance, Sci-Fi, Ecchi
Studios: 8bit
Producers: Sony Music Communications
Duration: 26 min
Rating: R+ - Mild Nudity

On a hot day of summer vacation, Charlotte's plan to spend time alone with Ichika at his house is somewhat ruined when Cecilia gets the same idea, later followed by Houki, Lingyin and Laura. The next day, Houki helps out at a summer festival being held at her family's shrine and is surprised when Ichika shows up.

(Source: Wikipedia)