My beloved stepmother who raised me alone was taken away by my worst friend...

Saint-san isn't a real mother. When I was a child, my father remarried, it was Sei. After my father passed away after a year of marriage, he raised me on his own. As a mother and a woman, my dream of having a crush on Sei was to make Sei even easier and happy. However, his dream was collapsed by the hands of his bad friend Takato. Takato uses me to approach his mother, faking illness and leaving early to approach Sei. I was so nervous I quickly returned home, and saw a shocking sight...