Tess Monaghan, confined by the final months of her pregnancy, becomes fixated on a young woman in a green raincoat who walks her dog daily across the street, until the dog appears alone, sparking Tess's suspicion of foul play. The protagonist's objective is to uncover the truth behind the disappearance of the woman in the green raincoat, a task complicated by her physical limitations and the isolation of her condition. The primary forces opposing her are the unknown circumstances of the woman's fate and Tess's own inability to actively investigate. The narrative unfolds from Tess's perspective, confined to her home, observing the world outside her window.

The premise of a homebound protagonist solving a mystery through observation sets up a classic whodunit with a unique constraint. The narrative likely relies on Tess's sharp intellect and her ability to piece together clues from afar, creating a tension between her physical limitations and her mental acuity. The focus on a seemingly ordinary event—a woman walking her dog—escalating into a potential crime suggests a grounded, character-driven mystery. The story appears designed to engage readers with its confined perspective and the gradual unraveling of a potentially sinister event.