104. The Disappearances

No release date yet

The Disappearances

103. Killer Spores

No release date yet

Killer Spores

102. Death Scouts

No release date yet

Death Scouts

101. Pilot

No release date yet

Pilot

17. Deadly Carnival

No release date yet

Mark goes undercover to investigate members of a carnival planning to break into a museum. The only way to break into the museum is through an underwater tunnel, through which only Mark can swim. When he is approached, he refuses. The owner of the carnival is then kidnapped and threatened unless Mark helps.

16. Siren

No release date yet

While investigating the mysterious loss of three ships in one part of the ocean, Mark and the crew of the Cetacean encounter a submarine operated by a modern-day pirate. The pirate has captured a mermaid that can produce a hypnotic siren song, which mesmerizes anyone who hears it, even Mark.

15. Imp

No release date yet

An impish little man enters an underwater station and causes the crew to become irrational simply by touching them. After three crewmen die the F.F.O.R. hears Duke, the last crewman, talking over the radio in a childish manner and investigates. Mark swims over and brings Duke over to the Cetacean, not knowing the imp has stowed aboard.

14. Scavenger Hunt

No release date yet

Mark encounters Muldoon, who is using a sea monster to make island natives sacrifice young girls to him.

13. Deadly Carnival

1978 - Season 1

C.W. develops a Jekyll-and-Hyde personality after swallowing a mysterious liquid.

12. The Siren

1978 - Season 1

An underwater landslide transports Mark to Verona, Italy... in the days of Romeo and Juliet.

11. Imp

1978 - Season 1

Schubert attempts to make a satellite weapon to knock out the Earth's communications. However, to power the weapon he needs the energy crystals protected by a forcefield under the ocean. The crystals actually power the forcefield that protects an underwater city.

10. Scavenger Hunt

1978 - Season 1

Mark is somehow linked with a man named Billy, existing in a wild west town, who appears to be his twin. Investigating, Mark arrives in the town and discovers Billy had the same webbing as Mark but has had it removed.

9. C.W. Hyde

1977 - Season 1

Using his genetic scientists, Schubert produces a giant jellyfish which he intends to release unless his extortion demands are met.

8. The Naked Montague

1977 - Season 1

The oceans are leaking through a fissure in the ocean floor. A conman named Muldoon agrees to guide Mark through the fissure to investigate. However, Mark is unaware that giants inhabit the other side of the fissure and Muldoon has already stolen gold from one of them.

7. Crystal Water, Sudden Death

1977 - Season 1

Mark, investigating a power outage, discovers a centuries-old hawk statue from the legendary civilization of Mu. The statue, when used properly, can remove the power from a large area. Schubert discovers the power of the hawk statue and Mark must prevent him from taking it.

6. Shoot-Out at Land's End

1977 - Season 1

When a multimillion-dollar underwater probe malfunctions and begins attacking any ship that travels near it, Mark must reason with its highly advanced brain and convince it to stop

5. Man O' War

1977 - Season 1

Schubert threatens to cause worldwide flooding by using powerful microwaves to melt the earth's polar ice caps, unless the government turns Mark Harris over to him.

4. Giant

1977 - Season 1

The oceans are leaking through a fissure in the ocean floor. A con-man named Muldoon agrees to guide Mark through the fissure to investigate. However, Mark is unaware either that giants inhabit the other side of the fissure or that Muldoon has already stolen gold from one of them.

3. The Hawk of Mu

1977 - Season 1

Mark, investigating a power outage, discovers a centuries-old hawk statue from the legendary civilization of Mu. The statue, when used properly, can remove the power from a large area. Schubert discovers the power of the hawk statue and Mark must prevent him from taking it.

2. The Mudworm

1977 - Season 1

When a multimillion-dollar underwater probe malfunctions and begins attacking any ship that travels near it, Mark must reason with its highly advanced brain and convince it to stop.

1. Melt Down

1977 - Season 1

Schubert threatens to cause worldwide flooding by using powerful microwaves to melt Earth's polar ice caps, unless the government turns Mark Harris over to him.

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