Every midnight, the Nightingale leaves Ashbridge Central.

It is no ordinary train.

Beyond the city walls, the railway crosses drowned villages, vanished stations and tracks that remember the dead. Its passengers carry unfinished journeys, forgotten names and destinations that should not exist.

New patrol officer Thomas Henshaw expects rules, timetables and tickets. Instead, he joins a crew charged with keeping the haunted railway in order: stern conductor Beatrice Holloway, relentless driver Martha Briggs, Inspector Mercer, the enigmatic Gideon Vale and a silent boy known only as Coal.

Together, they must face ghostly branch lines, false conductors, impossible stations and something ancient beneath the rails-something learning the railway's rules, stealing its destinations and searching for a way into Ashbridge.

As each journey draws the Nightingale deeper into danger, Thomas discovers that a ticket can change a fate, a timetable can become a trap, and some passengers have been waiting far too long to arrive.

Because the railway never forgets a journey.

And beneath the Line, something is still waiting to come aboard.