For weeks our screenwriter had been haunted by dreams of gutters, drainage culverts and sewage pipes. His subconscious telling him something, but what? And then it clicked. Trapped in an intractable position, what his heroes needed more than anything was a maintenance tunnel. Everything needs maintenance, he thought, so why shouldn't there be a tunnel there? Toss in an extra janitor and no-one will ever think twice about it.

All film buffs are invited to listen in to our movie-guessing show and see if you can identify our mystery Hollywood film from nothing more than a short clip dubbed into Chinese. Think you know the film? Write Echo at echo@popupchinese.com with your guess to be entered in a draw for a month of free premium access to Popup Chinese. Happy Mid-Autumn Festival too!