The only things on stage in way of a set are four chairs, and during the course of the play these four chairs serve to symbolize a variety of props, thus allowing the stage space to adapt freely to the theatrical developments.
The play involves four characters, the eldest son of the family, the eldest sister, the second son and a woman who is apparently his wife.
The second son has taken a peek at the contents of the box that the father had said must never be opened and is now afraid that the others will be angry at him for doing so.
The eldest son pulls out of his pocket what appears to be the dog Taro that the second son had once found and brought home. But it is no more than a phantom of Taro small enough to hold in the palm of his hand. He says that the box the second son had opened was the box that he used to hide the stray dog Taro in and the box that their late father had put the dog’s body in after it died.
Now the second brother’s wife enters with news that the father has died. The wife had been caring for the ailing father all this time. Then it is already the day of the funeral service. However, what was supposed to be the father’s funeral has suddenly shifted to talk about Taro’s funeral, and in the process it is now uncertain whether it is the father or the dog that has died.
The four family members gathered for the funeral service are talking about their memories of finding and taking in Taro, a dog no larger than the end of a finger. The terms they use to describe Taro, however, begin to create associations with some sort of strange or frightening creature rather than a dog. Before we realize it, the chairs of the funeral service have become the seats of a train that the four are taking to the seashore. The eldest daughter says that Taro came from the sea and they will return him to the sea. The box containing Taro’s body—which they have frozen—is up on the overhead rack in the train, and after a while a sticky liquid begins to drip down from it.
The second son’s wife tells her husband that Taro is their unborn child.
On the way to the seashore the four stop at a fertility (childbirth) shrine. The second son tries going down through a damp womb-simulation cave. In one chamber with a flow of hot water a decomposing, repulsive Taro tries to snuggle up to the second son, terrifying him and causing him to flee. It turns out that the chamber connects to a seaside hot spring spa and the four decide to take a hot spring bath. And it turns out that the spa happens to be their hotel for the night. Without even going out, the sea comes to them, they are told.
When the sea finally comes, it engulfs the second son. His wife saves him but Taro has died, they are told. Its body has dissolved.
On the beach the four open Taro’s box and look inside. When they do they find it is now a coffin with their father’s body inside. Thus it turns into a scene where they pay their last respects to their departed father. When the second son asks if this is really their father, the other three nod. There is an air of longing and regret as the four peer into the box/coffin.
As they set the box adrift on the water, each of the four let out their individual feelings in their final “
.” But the current of the tide pushes the box back to the beach. They try their best to push the box back out to sea, but each time the result is the same. The perplexed four stand there with their arms folded …