Tsuki no Shizuku

Youhei Amano has been lazily wasting his time away at home during summer vacation. One day, he happens upon a want ad in the classifieds for a part-time job as an employee for the Amaba Family. Youhei jumps at the name; the Amabas are prominent millionaires in his hometown, Hirano. Curious about this wealthy family, Youhei applies for the position. He is hired! Residing at the Amaba estate are 3 sisters: Shizuka, Kaoru, and Mayo. Hitomi the maid and Genjuro the butler also live there. Genjuro's existence is nothing but a hindrance, but life is exciting being surrounded by beautiful girls. With enough said about that, Youhei begins to get curious about a certain door within the mansion. No matter whom he asks about the door, he gets the same evasive, negative response. "What is on the other side?" he asks himself. There seems to be some connection between the history of the Amaba Family and their grip over the town of Hirano from way back...

[From gamelexgs]