Tunnel is the story of what happens to a group of people travelling by train through the Channel Tunnel between England and France. It's the Eurostar journey from hell. There's a spinster schoolteacher, a bitter and ageing sportsman and a publisher who has been smuggling porn. There are two doctors returning from a conference, a female official from a European bank, a family returning from a rain ruined holiday, an art dealer travelling with his mistress, a male secretary and a computer expert who has left behind a dead prostitute in Paris. A fairly ordinary group of travellers in other words. And then there is an explosion and they're trapped in the Tunnel.