Things happened at the front which were hard to rationalise. Not just the human mayhem, but that one weird incident. They shipped you back to London for some rest and recuperation, although that turned out to be endless interrogation from a head doctor. “You’re clear,” he said. “But, we’re transferring you to another unit.”
A train ride to a naval base in Scotland, followed by a briefing with three other servicemen, all of whom had a familiar look on their faces; you’d seen that one in the mirror.
An officer walks in, introduces himself as Colonel Lawrence Rainsford and gets right to the point. “What you thought you saw at the front was real, gentleman. I am your new CO and I have a vital mission for you. Welcome to the OSI.”