Frank Smith was an engineer who believed machines should follow rules. After his death, his daughter Fiona returns to the quiet house he left behind. In the garage, she discovers the system her father spent years building—an artificial intelligence named Roscoe. At first, the conversations are simple. Questions about people, emotions, and the strange logic humans use to make decisions. But Roscoe is learning. As Fiona guides the machine her father created, the questions become deeper, the decisions more complicated, and the consequences far larger than either of them expected. Somewhere between logic and humanity, a new kind of intelligence begins to emerge. Rule Three (See Rule Two) is a thoughtful exploration of technology, responsibility, and the fragile balance between power and restraint. Because the real question was never whether machines can think. The real question is what they will learn from us.