Lines on the Water opens at midnight on the St. Clair River, a small boat without lights and a heat signature that triggers a rapid intercept. Rayvn Rowe maps the real defenses at Port Huron: shoreline sensors, Air and Marine aircraft, Coast Guard patrols, and the command centers that stitch it together. Then she tests that system against three documented cases: a June 25, 2024 river landing that ended with arrests on both shores, an October 26, 2023 jet-ski run tied to 36 Glock pistols, and a June 12, 2025 Blue Water Bridge stop that uncovered 187 kilograms of cocaine. Solo voice, no reenactments, only verified records. How the net works, where it fails, and what it costs.