The lake - Banana Yoshimoto

A young woman moves to Tokyo after the death of her mother, hoping to overcome her grief and start a career as a graphic artist. But she spends her time staring out of the window, only to realise that there is a young man across the street staring out of his window too. They eventually embark on a hesitant romance, until she learns that he is the victim of a childhood trauma. Visiting two of his friends who live a monastic life beside a beautiful lake, she begins to piece together clues that reveal that his troubled past includes a bizarre religious cult.