Harumachi Kagerou

The protagonist, Asami Teruhiko, has a young sister. His parents are already dead, and he lives alone with his sister, whom he loves more than anything else in this world. He works hard to make her happy.

Unfortunately, she dies of leukemia. The protagonist spends several days at home crying by himself, until he decides that since he cannot live without her, he must join her.

Teruhiko goes on a trip to search for a beautiful place to commit suicide.

He climbs to the precipice of a very beautiful hill. Right before he jumps, a girl screams for help. Her crippled older sister almost falls from the precipice in her wheelchair.

After Teruhiko saves the life of the girl, the younger sister asks him to stay a night in her home, since that small town doesn't have a hotel. The protagonist doesn't have anything to lose, so he agrees.

This is just the start point of the game. The protagonist meets:

Miyuki: the sad and lonely, crippled girl
Shizuku: the cheerful and cute girl who loves anime and manga
Sayoko: the lonely mother of Miyuki and Shizuku
Satoko: the girl who manages a shop and lives with her grandmother
Ai-chan: the energetic and cute loli girl who has a “suspicious” relationship with Kazuo, a policeman

By interacting with all these girls, the protagonist finds a new reason for live, and finally finds his true love.

(Adapted from a description by fhc)