As the title of this novel indicates, this story is about dolphins - specifically about the dolphins there were around when the deadly tsunami of 2011 hit the eastern coast of the main islands of Japan.
It follows the adventures of an adolescent dolphin, Mako. When a tragedy occurs, he blames himself for it and decided to leave his pod. He meets other young female - then the tsunami strikes.
Through meeting members of other pods, and through encountering other species such as sea lions and whales, Mako:s core beliefs about the nature of life are challenged - and challenged again.
Most of all, he is challenged by what he learns about a species he has always adulated before now, especially where they loved his antics - humans. He is to learn that in southern regions and further west, that sometimes humans, instead of rewarding him with fish, like to capture dolphins - and much worse.
Those readers who enjoy animal stories where the animals, along with their communities, are anthropomorphised, should love this tale, which is also, very much a coming-of-age story. There is not just the horror and trauma of the tsunami, but also depths of cruelty that humans are capable of, where they believe that animals are not sentient. What makes novel more poignant is the reminder that the brains of these creatures are larger than those possessed by humans. These mammals may easily have their own myths and ways of making sense of the world, along with the same need for community ties that we do. Whether or not they will.also learn to hate humans and act on this, is moot.
Needless to say, the horror of Fukushima is also something that Mako and his fellow dolphins are aware of. The writer is clearly aware of ecological issues too, though the writer does mange not to preach.