The river that disappeared

Ronald and Sokha compare the old map with a simple modern street map. Tony keeps watch on a shelf. Empty case nearest the doorway, instrument on bench.
Ronald: This waterway has disappeared.

The stranger snatches the empty brown case through the open doorway. Tony launches from the shelf. Map remains on bench.
Tony: Put that down!

Thief runs through ordinary shop street carrying case; Tony pursues above him, Ronald follows with folded map. Sokha locks her shop behind them.
Ronald: Tony, wait!

Thief turns sharply into a side lane. A brass pendant with three-wave emblem falls from a broken cord at his pocket.

Tony swoops down to retrieve the pendant using his talons. The thief vanishes around a corner.
Tony: Careless of you.

At low riverside wall Tony sets pendant beside Ronald’s map. Sokha catches up. All three see same three-wave mark.
Sokha: I know that mark. The old pump workshop.