In a first-class carriage of a train speeding Balkanward across the flat, green Hungarian plain two Britons sat in friendly, fitful converse. They had first foregathered in the cold grey dawn at the frontier line, where the presiding eagle takes on an extra head and Teuton lands pass from Hohenzollern to Habsburg keeping—and where a probing official beak requires to delve in polite and perhaps perfunctory, but always tiresome, manner into the baggage of sleep-hungry passengers. After a day’s break of their journey at Vienna the travellers had again foregathered at the trainside and paid one another the compliment of settling instinctively into the same carriage. The elder of the two had the appearance and manner of a diplomat; in point of fact he was the well-connected foster-brother of a wine business. The other was certainly a journalist. Neither man was talkative and each was grateful to the other for not being talkative. That is why from time to time they talked.
One topic of conversation naturally thrust itself forward in front of all others. In Vienna the previous day they had learned of the mysterious vanishing of a world-famous picture from the walls of the Louvre.