The Wall
The sea wall is what keeps Calder alive. It runs along the whole front of the city, nine million people stand behind it, and its sluice gates are numbered. Gate six is the one nobody talks about.

Calder should have drowned a century ago. The wall is the reason it did not.
It is not one structure but a long series of them: bulwarks, sluices, pumping stations and gates, each numbered, each maintained by someone who would rather not think about the arithmetic. From the Sump you see it as a cliff. From the Lift you see it as a line.
The gates
The sluice gates let the sea in and out on a schedule that Morrow-Kade publishes and nobody reads. They are numbered along the wall. Most of the numbers mean nothing to most people. One of them is different.
Gate six is named in the stories people tell about the night the Sump drowned. It is never explained. This page does not explain it either.
In the story
The wall frames Gate Six from its first chapter to its last. Rook counts everything, and in time he starts counting gates.
More from Calder

The Shear
The space between parallel Calders.

The Sump
Flooded streets, walkways, noodle bars, iron stairs. Rain that never stops.
Appears in Gate Six, Book One of The Shear. Back to the world of Calder.