Keith and Sherry Parker are the owners of a cottage that for many years was run as a guesthouse. During the Second World War a mysterious lodger with suspected ties to the Axis powers was captured after allegedly conducting secret reconnaissance missions in the area. While Australia's official military history refutes the notion of foreign spies operating on Australian soil during the War, Adam goes in search of eyewitness accounts to piece together this fascinating story of espionage.

Could there be a link between an unidentified body discovered at Western Australia's Garden Island and the mysterious hillside lodger? What Adam discovers could result in a rewrite of Australian wartime history.

The Parkers also set Adam the challenge of seeing whether he can determine the date and purpose behind a curious old tomahawk that was dug up from their garden. A forensic investigation and a detailed analysis of local records help Adam identify the relic and reveal where the Parker's home fits in with the colourful history of the local area.