1961
Sergeant-Major discovers a bubbling pit and reports his finding to Minerva and Doc. The learned fish fears that the pit might be the beginning of an underwater volcano and request permission from the mermaid to investigate. Meanwhile, the Baron and Trigger plot to capture the fish and use them as bait to lure Diver Dan to a scalding death.
1961
Diver Dan attempts to persuade Horace to become the star attraction at an aquarium, since he is the last of his species in existence, while Finley and Skipper Kipper argue that Horace should stay in the ocean with the rest of his fish friends. Meanwhile Baron Barracuda, with his henchman Trigger's assistance, has broken out of jail. Dan, Horace, Finley and the Skipper immediately join the search for the escaped prisoner.
1961
Diver Dan, Finley and Horace are lost in the middle of the Sargasso Sea, a jungle of seaweed with no paths leading to safety. Finley asks Dan how he would find his way if he was lost on the ocean surface and the diver explains how he would use the compass or the North Star to guide his way. Horace suggest using the flow of the Sargasso current which is known to lead south. Just as the three friends are making headway, a powerful storm strikes the ocean floor.
1961
Diver Dan, Finley and Horace take refuge during a savage storm that rages across the floor of the ocean. Once the storm abates the trio follow the Sargasso Current to Teetering Rock, which marks the entrance to the seaweed bed. Dan and his friends return to the nearby cave to pick up the equipment the diver cached before entering the kelp jungle, they become trapped when Baron Barracuda and Trigger topple Teetering Rock on top of the cave entrance.
1961
The lair of Baron Barracuda is darkened with ink from the octopus. Finley Haddock frets as to how the shell-o-phone might be recovered, with the recovery party unable to see into the cave. Diver Dan sheaths his knife. Doc Sturgeon says that the prognosis is unpromising. Trigger Fish asks the Baron if he is still present. The Baron tells him to be quiet, and asserts that my secret weapon has been successful. Trigger, in the dark, grabs a fish by the tail. The Baron yells in pain and tells Trigger that the tail is that of the Baron. Finley suggest that Seabiscuit the Seahorse be sent to Miss Minerva for help, that Miss Minerva will surely know how to combat the Baron's secret weapon. Dan endorses the idea, and calls to Seabiscuit, who whinnies. Dan asks Seabiscuit if he can go to Minerva for help. Seabiscuit whinnies and swims away. At the place of Miss Minerva, she is watching Goldie the Goldfish swim in her bowl, with Scout Fish present. Scout announces the approach of Seabiscuit. Minerva notes that Seabiscuit is alone and looks very worried. The camera pans briefly to Gabby the Clam, who says Trou-ble.. As Seabiscuit arrives, Minerva asks him what the matter is. Seabiscuit whinnies and Minerva translates. She notes that it is no surprise that the baron would do something dark. Scout remarks on the wickedness of the Baron. Gabby says Glow fish. Minerva asserts that, indeed, Glow Fish is their one hope; that, with his miraculous head-lamp he can lead the recovery party from the ink. She directs Seabiscuit to the Bottomless Pit, to summon Glow Fish and lead him to the rescue. Seabiscuit swims away. Seabiscuit comes to three signs on a post. The top-most says MinERVa'S PALacE and points to the right. The next one down points forward and says TEETERING ROCK in teetering letters. The bottom-most sign says BOTTOMLESS PIT and points forward and to the left. Seabiscuit scans the signs and then swims in the direction for the Bottomless Pit. As he continues, he passes another sign, which points forward and downward and says BOTTOMLESS PIT. Seabiscuit swims downward, whinnying. As he descends, Glow Fish (a fish with a stalked head-lamp) rises to greet him. (Glow Fish sounds rather like Digger O'Dell from The Life of Riley radio show.) After Seabiscuit whinnies further, Glow Fish says that he will come almost immediately, after finishing charging his batteries. He descends, and sounds like those of high-voltage induction coils are heard. Glow Fish is briefly seen at some sort of glowing electrical panel. Then, with Seabiscuit in the lead, they leave the pit. Finley moans that it seems that time is with the Baron. Dan says that the ink may take many hours to dissipate. Seabiscuit and Glow Fish approach, with Seabiscuit whinnying. Finley infers and reports their approach. Doc cheers that Seabiscuit has Glow Fish with him. Georgie Porgy pleads with Glow Fish to lead them out of the ink. Dan suggest that first Glow Fish should rescue the shell-o-phone. Finley agrees and explains to Glow Fish that the Baron and Trigger have stolen the shell-o-phone, and asks Glow Fish to snatch it away if he can. Glow Fish agrees to try; Dan says that this is more than the rest of the recovery party can do. The Baron senses that the recovery party is doing something unanticipated and expresses frustration. Glow Fish slips his snout into the shell-o-phone and begins to carry it away. The Baron demands to know what the strange glow is, and says that something is wrong. Glow Fish swims from the cave with the shell-o-phone; Georgie cries out happily of the success, then pleads again to be lead from the ink. Finley urges that the recovery party take the shell-o-phone back to Minerva as quickly as possible; he takes the shell-o-phone from Glow Fish. Doc endorses this idea, and then asks if Glow Fish is okay. Dan says that Finley and Georgie should take the shell-o-phone while some of the recovery stay behind to keep the Baron and Trigger in check. Finley and Georgie swim away. Glow Fish collapses. Doc says that the thin water and the effort of carrying the shell-o-phone have brought on acute anoxia. Dan cradles Glow Fish in his hands, and says that he must be returned to the Bottomless Pit as soon as is possible. Doc agrees, but frets that they may not be able to do so in time to save Glow Fish. Dan and Doc head for the Bottomless Pit, Dan carrying the dying Glow Fish.
1961
Trigger accidentally locks Baron Barracuda in the cage Diver Dan requested from his ship. Baron is furious when the Dan's captain pulls the cage to the surface and Trigger blames Horace for causing the debacle. Horace flees, thinking his friends want to capture him for an aquarium and the Baron and Trigger want to eat him.