Hook
Every lighthouse has a legal 'characteristic', its own flash pattern, like Fl(2) W 10s. When the Coast Guard automates her light, the last keeper is asked to type in its new pattern. She types in her husband's final ECG instead: the last nine hours of his heart, measured from the night he died in the hospital. Now the beam pulses his heartbeat across the bay in real time, dusk to dawn.
Escalation
- The trawlermen who fished with him recognize the stumbling, irregular rhythm within a week. They call it 'Tom's beat' and steer home by it. In fog the neat official patterns blur into each other, but nobody mistakes his. The harbor's near-miss count drops for the first time in years.
- Because the recording plays in real time, each night ends the way his did. Just before dawn the pulses stop and the beam holds steady. A steady white light means something specific on a nautical chart, and it isn't this. A ferry captain files a complaint, and the maritime regulator books an inspection.
- The town hears why the light changed and starts bringing her its own dead: a Fitbit export, a grandmother's pacemaker log, a stillborn's fetal Doppler. They can't go in the lighthouse, so people hang lamps in their windows, and by midwinter the whole coastline blinks with other people's heartbeats. It's beautiful, and it's also a navigational disaster, so the inspection is moved up.
- The inspector is a dry man with a tide table who turns out to be a decent one. He confirms she has broken federal law and must restore a standard pattern. Then he asks how long the recording runs, gets out a pencil, and quietly sets his compliance deadline for the first week of July.
✦ Twist
She set up the light in December, when nights last longer than nine hours, so every dawn the light finished on his flatline. The inspector worked out what she hadn't. Around April the nights get shorter than the recording, sunrise arrives first, and the light's sensor switches the beam off mid-beat. All spring and summer the light goes dark each morning with his heart still going. When she resets it to a legal pattern in July, the town has already learned that for part of every year, Tom makes it through the night.
💡 A real maritime rule (a light's 'characteristic') meets a real fact of astronomy (nights shrink in summer), so the ending feels inevitable and earned rather than magic: the planet's tilt does what the law and her grief couldn't.