Fish Swimming in Dappled Sunlight

"A Quicksilver Mystery That Flickers, Flashes, Twists And Turns." New York Times, 21 July 2022. From the author of The Aosawa Murders, one of the NYT Notable Books of 2020. Set in Tokyo over the course of one night, Aki and Hiro have decided to be together one last time in their shared flat before parting. Their relationship has broken down after a mountain trek during which their guide died inexplicably. Now each believes the other to be a murderer and is determined to extract a confession before the night is over. Who is the murderer and what really happened on the mountain?
In the battle of wills between them, the chain of events leading up to this night is gradually revealed in a gripping psychological thriller that keeps the reader in suspense to the very end.