Season 4

01 Point of No Return Episode 17th January 1961 Mike is trapped in a ""scubasphere"" when the cable attached to it snaps. 02 River Treasure Episode 214th January 1961 While surveying a remote river in the South American jungle, Mike is threatened by the jealousy of a man prospecting for emeralds with his wife. 03 The Destroyers Episode 321st January 1961 Mike investigates the source of a radar jamming signal that caused two ships to collide. 04 Vital Error Episode 428th January 1961 A famous newsman, convinced that he has a fatal illness, tries to end his life in such a way that his wife can collect his insurance, with Mike as a witness. 05 The Dancer Episode 54th February 1961 A scuba diving ballerina faces the possibility of underwater amputation when she catches her foot between the buckled plates of a sunken freighter. 06 Sperling of Lamatsue Episode 611th February 1961 After being accidentally caught in a fishing net, Mike challenges an Asiatic warlord by trying to retrieve a cache of medical supplies that the dictator has dumped into a river. 07 Rescue Episode 718th February 1961 Unaware that two of his treasure-hunting friends are trapped inside, Mike sets charges to blow up a sunken ship that is a menace to a busy shipping lane. 08 Mercy Trip Episode 825th February 1961 Mike scouts a path through mine-infested waters so that medical supplies can reach a China Sea port hit by a cholera epidemic. 09 Hot Tracer Episode 94th March 1961 Mike's efforts to retrieve a pair of radioactive cylinders are complicated by the presence of a headstrong youth to whom he's been giving diving lessons. 10 Sonar Story Episode 1011th March 1961 Mike uses sonar to foil a gang of underwater heroin smugglers. 11 Amigo Episode 1118th March 1961 A young Mexican boy helps Mike locate a safe entrance to an underwater fossil cave. 12 The Aquanettes Episode 1225th March 1961 Mike faces sharks and other unexpected difficulties while working with three pretty women undergoing astronaut training. 13 Survival Kit Episode 131st April 1961 Mike is hired by a local German consul to salvage a survival kit from the wreckage of a Nazi warplane in the Caribbean. 14 Expedition Episode 148th April 1961 While helping his former history professor search for pirate treasure off the North Carolina coast, Mike finds evidence that the underwater cave said to house the treasure has been tampered with. 15 Bionics Episode 1515th April 1961 Mike convinces a reluctant daughter to continue her father's work after he is killed testing an underwater electrical detection device. 16 The Defector Episode 1622nd April 1961 A man bribes Mike to continue giving lessons to an inept diving student whom he's stopped teaching. 17 Niko Episode 1729th April 1961 Mike heads a three-man team in an effort to disarm a pair of unexploded torpedoes at the bototm of a West Coast harbor. 18 Cougar Episode 186th May 1961 A restless youth and a college girl complicate Mike's attempts at capturing a poisonous lionfish. 19 Sub Hatch Episode 1913th May 1961 A heroic test pilot from the Korean War has his mettle tested when he must spend 24 hours with Mike in a makeshift decompression chamber after a dive to prevent the bends from killing him. 20 The Octopus Story Episode 2020th May 1961 Markings on the body of a dead diver convince a marine biologist that a tropical lagoon is inhabited by a killer octopus. 21 Quicksand Episode 2127th May 1961 One salvage diver disappears while diving on a sunken yacht off the coast of Yucatan, and Mike tries to see that two others don't share his fate. 22 Lost Island Episode 223rd June 1961 Mike teams up with a Mexican prison escapee to uncover nefarious activity on an uncharted Pacific atoll off the coast of South America. 23 Baby Episode 2310th June 1961 Mike must get past Jivaro Indians who are blocking his passage downriver as he attempts to get a young missionary's baby to a hospital for medical attention. 24 Confidential Mission Episode 2417th June 1961 Mike poses as a tourist on vacation as he tries to locate a hidden underwater missile launcher in the Caribbean. 25 Underwater Pirates Episode 2524th June 1961 Pirates try to snatch a sunken freighter away from Mike before he can salvage it for an old Navy buddy. 26 The Meet Episode 261st July 1961 While working for the U.S. Treasury to break a counterfeiting ring, Mike intercedes in a kidnapping. 27 Dark Evil Episode 278th July 1961 A pretty woman and her father, vacationing in the Bahamas, become killers after inadvertently eating a variety of fish that causes hallucinations. 28 Sunken Car Episode 2815th July 1961 A sunken truck points Mike to the murder of a political boss, and the killer is the father of a good friend of Mike's. 29 Hit and Run Episode 2922nd July 1961 Mike goes after an egocentric movie star who injured a friend of Mike's in a hit-and-fun speedboat accident. 30 The Saint Story Episode 3029th July 1961 While searching a Latin American harbor for a sunken statue, Mike discovers a UHF homing beacon being used to guide submarines into the port. 31 Impostor Episode 315th August 1961 A dead ringer for Mike is stealing diamonds from a sunken sports cruiser, but when Mike is accused of the crime, he is unable to establish an alibi due to his current top-secret mission. 32 Superman Episode 3212th August 1961 While on a diving expedition in Guatemala, a woman seeking to slow down her husband's frantic lifestyle deliberately sinks the boat they share, unaware that her husband is a diabetic and his insulin supply will be lost with the vessel. 33 Roustabout Episode 3319th August 1961 Mike's assistant is trapped underwater by an overturned truck containing drums of poison that could endanger a South American city's water supply. 34 P.T. Boat Episode 3426th August 1961 Mike helps test a remote control guidance device invented by a rich eccentric. 35 Starting Signal Episode 352nd September 1961 A naval officer of a Caribbean nation is sabotaging a series of experiments Mike is conducting with the Coast Guard. 36 Skipper Episode 369th September 1961 During hydroplane races, a friend of Mike's rams his craft into a Coast Guard ship, leaving Mike to investigate. 37 Crime at Sea Episode 3716th September 1961 Mike helps the daughter of his old UDT Commander investigate the man's death, which she believes was murder. 38 Round Up Episode 3823rd September 1961 Mike must find and disarm a torpedo that's been sent into the outflow tube of a hydro-electric plant.