Death by water

the long version

"[Kogito Choko] returns to his hometown village in search of a red suitcase rumored to hold documents revealing the details of his father's death during World War II, details that will serve as the foundation for his new, and final, novel. Since his youth, renowned novelist Kogito Choko planned to fictionalize his father's fatal drowning in order to fully process the loss. Stricken with guilt and regret over his failure to rescue his father, Choko has long been driven to discover why his father was boating on the river in a torrential storm. Though he remembers overhearing his father and a group of soldiers discussing an insurgent scheme to stage a suicide attack on Emperor Mikado, Choko cannot separate his memories from imagination and his family is hesitant to reveal the entire story. When the contents of the trunk turn out to offer little clarity, Choko abandons the novel in creative despair. Floundering as an artist, he's haunted by fear that he may never write his tour de force. But when he collaborates with an avant-garde theater troupe dramatizing his early novels, Choko is revitalized by revisiting his formative work and he finds the will to continue investigating his father's demise" --