This fourth book in the Series 'Men and Ships at War' is a description of the fatal encounter between Japanese submarine I-21, HMAS Mildura and SS Iron Knight off the south-east coast of Australia on 8 February 1943. In the early hours of the morning, the BHP Shipping vessel, SS Iron Knight, was sunk in 2 minutes by I-21. The sinking occurred in full view of HMAS Mildura, the corvette escorting SS Iron Knight's convoy, OC.68. Thirty-six merchant seamen lost their lives, many from Newcastle. Allan's great uncle, 'Dukesy' Forbes, also from Newcastle, was aboard HMAS Mildura. This book records for the first time the complete story of the sinking of the SS Iron Knight including the contribution of the Free French destroyer, Le Triomphant, which raced south and rescued fourteen survivors. The events surrounding the sinking on 8 February 1943 are indicative of the wider anti-submarine activities of the Australian Campaign.