Set in Japan, the book tells of Kou, his extraordinary life and the compelling thread that gives the work its title. It is powerful because it shatters the notion that every human being has of himself, of feeling that he is the protagonist of his own existence. Although it is an inevitable perception, Kou helps us to understand that this is not the case. He presents us with evidence of the fact that the real protagonist is someone else, an invisible presence who silently waits for man to do what he must, does nothing to show itself but never denies its being if it is sought. In the first part, the author narrates Kou's story, but in the second part, it is the invisible protagonist who speaks about himself and the man he inhabits, their roles, their missions and also what death means for both of them. It is about a man, but also about all men, because the sense of infinity that permeates the book belongs to every human being and the reader cannot help but feel it. It will be like sensing the beating of your own essence, which you have ignored or forgotten until now, but which you can now rediscover and discover why and for whom you are living along with it.