[2] Tragically orphaned by a car accident, the Kasugano twins travel to their grandparents' countryside residence in Okukozome via railcar, hoping to reconstruct the shards of a shattered life.

Uncertain of the future, Haruka Kasugano clings to memories of the past, hoping to find the strength he needs to protect his ailing sister.

As the tale develops, it tells four stories, each with one girl: Kazuha Migiwa, rich but kind; Akira Amatsume, polite but sad; Nao Yorihime, depressed but hopeful; Sora Kasugano, petite but fierce.

The main plot of the anime is presented in a multi-arc branching format that independently tells the stories of Kazuha, Akira, Nao, and Sora while sharing certain common episodes.

Yosuga no Sora was adapted into a manga of the same title, illustrated by Takashi Mikaze, and serialized from October 2009 to January 2011 issues of Kadokawa Shoten's Comp Ace magazine.

The OST for the anime adaptation, with music composed by Manabu Miwa (Manack) and Jun Ichikawa (Bruno Wen-li), consists of both new compositions and newly arranged versions of tracks from the original game.