Original title: Pure Marriage ～赤い糸物語 まどか編～
Aliases: Pyuamari, ぴゅあまりっじ
This is the first title by Lass Pixy, one of three low-priced titles, each focused on a different heroine.
Touma has reached a critical turning point of his life. He was asked to marry the daughter of the richest family in town, Serika, after incidentally saving her life. After hearing that he had become Serika’s fiancé, his osananajimi Madoka and imouto Sakura also declared themselves as their fiancées. While they are all very important to him, he can only choose one of them as his bride and they each pressed to be chosen while hiding their real intentions secret.