Melbourne, 1930, as the Great Depression is taking hold: Thirteen-year-old Morris Turner, a little anxious by nature, feels more at home gazing at the stars than spending time with his detached father Jude, a detective, and older sister, Lottie. When a young woman is murdered in Jude's home town of Gemini, he is assigned to solve the case. With fear and polio rising in the city, Jude reluctantly takes Morris and Lottie to the small town he left long ago.

At the family farm in Gemini, Morris meets relations who are strangers - an aunt, an uncle, and a cousin obsessed with detective novels - and is drawn into a community reeling from a murder and a financial crash. Without a clear suspect for the killing, suspicions have turned to the downtrodden, huddled in camps outside the town. But Morris is sure there is more to this case. With the help of new friends, he turns his attention instead to the people around him, confronting his fears and searching for a killer in a town full of mysteries - a search that will bring secrets old and new to the surface, and leave someone else fighting for their life.