Koenji Takeru and his wife, Reiko, have no children. Takeru himself is certain that there will be no more children in the future. It's not that either of them have a physical problem. They simply don't have much sexual intercourse. But what is the cause? It's a mental problem for Takeru... It's because of his lingering feelings for his stepmother, Misato. When they were young, a one-night mistake turned both their lives upside down. And finally, the day came when he could no longer suppress those feelings...