An alien winds up on Earth and spends millions of years roaming it as a shark until one day in the 1930s it decides to take the form of a human. It spends the following decades learning about humanity and growing as a person. In an interleaved plot line, in 2019 an ancient alien artifact is found in the Pacific Ocean and a marine salvage company investigates.
The growth of the alien as a human is very well written, from tentative and often disastrous beginnings to a finding of true purpose and even love. The descriptions of humanity from the alien’s often uncomprehending viewpoint are fascinating, in particular the part during the Bataan Death March, where the worst of humanity is on display.