When a sub is seen off the coast. It appears to be an old German U-Boat from World War II. A message is sent saying that unless their demands are met, they will kill thousands of people. They agree to a meeting and Steve is sent to meet with the person. The person claims that the sub has a cache of nerve gas which when released and depending on the wind will reach a populated area. Oscar decides to send Steve to get into the sub and to try and neutralize the threat. But Steve is captured and is shown the nerve gas. But the Admiral receives information that there is no nerve gas on the sub so he decides to attack it with Steve on board.
Did You Know?
Somebody in the production staff must have liked the number "509", since it is used for the submarine number in both this and the subsequent season's sub-related SMDM episode "Sharks". See more
In the first shot of the sub moving past the camera underwater, the sub is moving much too fast for the slowly-rotating prop to be pushing it. See more