"I first met my stepmom when I was in elementary school. It was spring, 2 years after my real mom passed away..."

His father who has been raising him all by himself after he lost his wife, had remarried. His son Daiki, despite having a rebellious streak, chose to accept living with his stepmother, for his father's sake. But the boy kept his distance as he didn't know how to approach her. So his stepmother Kaori slowly closed the gap with him.

"Just lengthen the 'ka' sound from Kaori, so please call me Kaa-san. (Mum)"

Kaori's gentle affection for him grew sincerely, and she would love him as if he were her own real son.
Daiki gradually accepted her as his mother, but at the same time he was also becoming attracted to Kaori, who was still a young and beautiful woman.

One day, he had just come home after getting caught in the rain, when he happened to walk in on his stepmother in just her undies, as she was in the middle of changing clothes. He kept his feelings of love hidden as he grew up, and twisted desires began to pile up while he tried his best to be a "good son" to a "kind stepmother", a relationship he did not want to destroy.

Daiki's secret love was supposed to end one day as just a "bitter first love", when his father's death suddenly changes everything...

This is a story of pure love growing between a stepmother and her son.

(Source: DLsite)

Part 1 released at Comiket 97, part 2 released at Comiket 98.