Through the Sluice

Don't get emotional on me now; there is still plenty of ground to cover. I pocketed my mica periscope and marched straight around the stone bend toward that iron sluice gate. The lower rim was stuck open just three inches, wedged by packed river gravel and ancient silt. I dropped onto my knees, planted both boots against the curved brick floor, and dug my brass safety pin into the gritty blockage. A heap of dry pebbles rattled loose, opening just enough clearance. Lying flat on my stomach, I slid sideways under the heavy, rusted teeth of the gate. On the other side, the tunnel widened into a dry, vaulted brick chamber with air that tasted clean and cold.