Rinne no Lagrange: Kamogawa Days
English title: Lagrange: The Flower of Rin-ne – Kamogawa Days
Japanese title: 輪廻のラグランジェ 鴨川デイズ
Type: OVA
Episodes: 1
Source: Original
Genres: Comedy, Sci-Fi, Slice of Life
Studios: Xebec
Producers: Production I.G, Bandai Visual, Yomiuri Telecasting, flying DOG
Duration: 43 min
Rating: PG-13 - Teens 13 or older

As Yoko has her assistant scour the seabed in search of something, Madoka, unable to pilot Midori properly again, returns to Kamogawa to see the New Year in. Upon returning home, Madoka receives New Year's letters from Lan and Muginami, updating her about what's going on in their lives, to which Madoka makes a prompt reply. As the months pass by and Madoka moves up a year in school, Lan and Muginami visit an intergalactic replica of Kamogawa on the tourist planet Polyhedron.

Takes place between seasons 1 and 2.

(Source: Wikipedia)