After her mom re-married, Ema moved into the Asahina Family House and acquired eleven brothers. Ema intended to live peacefully with them as a family, but the sudden appearance of a girl in an all male household causes discord. Going on with their lives, the brother's feelings for Ema change and the start of a same roof forbidden romance begins.

In Brothers Conflict: Brilliant Blue, Ema has the option of romancing Ukyo, Azusa, Natsume, Louis, Iori, and Wataru.