Lagoon is a story of first contact, sort of.
It's set in Lagos, Nigeria, and it sees an alien spacecraft landing in the seas off the city. The story unfolds the events of the night following the craft's arrival, focusing on three Lagosians in particular: Adaora, a marine biologist with a struggling marriage; Anthony, a famous rapper; and Agu, a battered and disillusioned soldier. And Ayodele, the aliens' ambassador.
What I found most interesting about Lagoon was its deceptive simplicity. The plot moves swiftly and violently, through riots and bigotry and vengeful mutated swordfish (yes, you read that correctly), and there's plenty of gore, enough that I had occasionally to stop reading and do something else for a bit. But as the story continues it picks up layers and reflections and echoes and meanings, becomes more than a disaster novel: becomes a portrait of a city and a country. The Nigeria of Lagoon is a dangerous place, one full of repression and corruption and religious bigotry, but it's also full of life and history and potential.
Lagoon is a novel that's aware of its genre and of the limitations of that genre. It's profoundly aware of the Western-centrism of SF, and to me it feels like a call to the SFF community to widen its perspective, to widen all of our perspectives. The aliens' first contact isn't with humans, it's with the creatures of the sea: the seas make up 75% of the Earth's surface, so why do we always assume that aliens will be interested in the other 25%? The narrative hops through viewpoints (this isn't as annoying as it sounds): we see through the eyes of bats and of swordfish and of Nigerian gods as well as a number of human eyes. Experience isn't singular. It refuses to adhere to the generic and ideological boundary of science fiction/fantasy: the book contains aliens and gods, science and magic. Lagoon is a novel very much more than the sum of its parts, carrying (much like the water whose name it bears) deep complexities beneath its apparently simple surface.