March 1812. - Whilst patrolling the sea lanes off the Swedish island of Hanoe, Captain James Carey of His Majesty's Royal Navy frigate HMS Hector, sights a French brig sailing north towards the Swedish coast. On engaging the brig, the French ship strikes its colours and surrenders but when questioning the only surviving French officer, James becomes suspicious, believing the officer is not what he claims to be. Further interrogation leads the British to conclude that the French, along with several high-ranking officers of the Swedish navy, are planning an attack on the island's British garrison. A passionate affair with Anna, the beautiful daughter of a treacherous Swedish fisherman, leads James into discovering French plans for a full-scale invasion of the island. A daring scheme to defeat the invasion goes ahead until fate intervenes to deal an unexpected hand.