Titles read: "TALE OF TWO SUBMARINES".
Various locations of events.
Footage from 1939 shows the scene of the sinking of the submarine Thetis in Liverpool Bay. Rescue workers try to recover the vessel. Relatives of the crew wait in Birkenhead for news (99 men died). We then see several shots of the rebuilt Thetis at sea, now renamed Thunderbolt.
Aerial view of recovery work in 1939 after the American submarine Squalus had sunk. The vessel is brought to the surface. Several shots of the rebuilt Squalus, now renamed Sailfish, that is in service for the US Navy.