david jason and a family favourite play a character in the exact same style a he do in a touch of frost and in this ridiculous and predictable thriller . in this 2 parter and david jason play the character of a old wwii seaman who be call in by the navy when his submarine re emerge after disappear in the war . only david jason jack hardy survives from the original crew but he suffer from memory loss and and have to piece together his movement from a series of flashback when take back inside the ship . the story then become laughable when the navy decide and for some reason and to re enact the last voyage of the submarine by piece together the movement from the captain log . after accidentally sink a russian submarine they come under attack from german wwii aircraft and jack hardy realise that someone be fill in the incomplete captain log . good for a one off if you do not want to do much think but easily forgotten .