The Laundry is a secret branch of the British Civil Service, dedicated to protecting the United Kingdom against Horrors from Beyond. In your time in the Laundry, you've seen your share of terrible, frightening documents: grimoires bound in human skin, soul-eating computer code, ISO9001 compliance assessments. None, though, are as terrifying as the thing sitting on your desk.
It's a plane ticket. The Laundry's budgets are more tightly bound than a summoned shoggoth. If they're paying for your flights, then something hellish is about to happen overseas, and you're in the firing line.