Kiyotake, the elder son of the family, is being trained to take over his father Shiro’s factory, and he has grown content with his image as the under-achieving older brother with a talented younger brother, Kiyomi. While they are at home one day a rock falls from the ridge behind the Kamiyama house and hits Kiyomi in the head. He is hurried to the hospital.
Three days later, Shiro’s younger brother Reiji and his wife Natsuki visit Kiyomi’s hospital room. Natsuki is an interior coordinator and Reiji lives as a househusband. Reiji acts strangely, he suddenly waves at something out the window and then leaves. On a whim, Kiyomi makes the same gesture of waving out the window, but it appears to be answered by the sound of a crash outside.
A few hours later, a fellow worker of Kiyomi’s named Kimi Mochida comes into Kiyomi’s hospital room. She is injured and says that she was distracted when she saw Kiyomi waving out the window and had an accident as a result. Just then a phone call arrives from Kiyomi’s boss, saying that he has been removed from his position in the project he was leading.
His will to work now waning, after leaving the hospital Kiyomi begins attending the strange meetings being held by Reiji at the riverside. Reiji seems to be looked up to as a sort of spiritual leader by two former stay-at-homes, Ogawara and Mashiko. Reiji, in turn, appears to look up the homeless man Wakisaka as his ‘master’ who has disguised himself thus to live in the common world.
Reiji believes that he is helping to “maintain the balance of the world” by answering the ‘voices’ that he hears within himself and acting on them. His actions at the hospital had been one such case. Kiyomi continues to make fun of Reiji and his lot, but he still can’t leave their company.
Kiyomi has come to visit Mochida in the hospital, where he learns that a late friend of Mochida had died in the same hospital room after being struck by a tree that fell from a ridge.
Meanwhile, Shiro has sent his wife Kae to ask Reiji’s wife Natsuki not to let their son Kiyomi meet with Reiji anymore, but Natsuki dismisses the request, saying that Kae pays too much attention to the boy because she is a housewife with too much free time.
Kiyomi is now saying that he is going to quit his job at the trading company. After being dismissed as no more than a housewife, Kae is also saying that she is going to go out and get a job. As for the father Shiro, he is now fretting that it is Reiji’s fault that everything is going awry in his family. Kiyotake takes his father’s side, but no one pays him much heed.
A scene of reminiscence: When Reiji was in elementary school and his mother was in the hospital, to relieve his loneliness he got into the habit of saying ‘Good night’ to his absent mother before he went to sleep. One evening when Reiji older brother Shiro teased for that bedtime habit and he didn’t say good night to his mother, it was late that same night that she died in the hospital. Believing that answering the ‘voice’ from his mother to say good night had kept her alive, Reiji began saying good night not only for his loved ones but for the whole world. Shiro couldn’t understand Reiji and what he believed.
Kiyotake’s friend Katakura is making fun of Ogawara and Mashiko at their riverside gathering place. A fight erupts that even brings Wakisaka in, and in the heat of it Ogawara stabs Katakura with the point of an umbrella. By this time rain has suddenly begun to fall.
In the hospital room where Karakura and Wakiska are recovering, Ogawara is claiming that he isn’t to blame, because he was only answering the orders of a ‘voice’ he heard. Realizing that the voices that could protect people’s lives could also inflict injury on people, Reiji has begun to apologize. Seeing this, Ogawara looks on Reiji in disdain. Concerned about the events, the Kamiyama family has gathered. Shiro and Reiji voice their conflicting thoughts; there is no common ground to be found between them.
A hard rain continues to fall. Kiyomi now says that the rain won’t stop because Reiji and his disciples have not been able to answer the voices and the ‘balance of the world’ is crumbling. Reiji confesses that since the incident he doesn’t hear the voices anymore. Kiyomi tries to convince them that the important thing is listening to the voices, not carrying out their instructions. We have to make our own decisions about the actions we take, he tells them.
In answer to a ‘voice’ Ogawara attempts to throw himself into the rain-swelled waters of the river, but Mashiko tries to hold him back. Reiji and Kiyomi come running to help and wrestle Ogawara to the ground to stop him. At this moment they get news that the ridge behind Kiyomi’s house has crumbled down.
Shiro is safe, having been the first to escape the landslide. Afterwards, it is as if a curse has been lifted from the people. The rain has finally stopped as well. Kiyomi, who has now quit his company, says he is going to construct retaining walls to remedy the unsafe ridge that has been the source of the fallen rock, the fallen tree and the recent landslide. Shiro objects angrily. But a seemingly older and wiser Kiyotake intervenes, telling his father that he will take care of the factory, so Kiyomi should be left free to do as he wishes.
Some days later. At the river, Reiji and the others answer a ‘voice’ by sending Kiyomi to meet Mochida as she comes out of the hospital this day. It appears that the world has regained its balance, though it is a different form of balance from what was before.