"Plunder Island" (published in 1933) is a landmark Thimble Theatre storyline. The tale takes Popeye on a dangerous adventure where he must face all manner of foes, from pirates, to witches, to even monsters, in order to reach the fabled island of treasure; 'Plunder Island' is also the name of the locale where much of the action takes place.
The story begins in Popeye's newly acquired restaurant from the last storyline, where he is informed by Wimpy that a rough-looking fellow has come to see him. Upon meeting the rough sailor type, he and Popeye immediately begin punching and harming each other in several ways, much to the shock of those present, including Wimpy and Olive. Olive then asks Wimpy to go seek help from the police to break up the fight, but as soon as Wimpy leaves, Popeye and his "opponent" happily shake hands and Popeye reveals that the rough-houser is actually his old friend and former crewmate "Salty" Bill Barnacle from 20 years earlier, and that their brawl was actually the secret handshake of their old brotherhood, the Sea Dog Club. Meanwhile, Wimpy manages to find a team of police officers and has them follow him back to the restaurant to stop the "fight", but, once they arrive, the policemen are less than pleased to see two fellows happily getting along rather than fighting, and quickly plan to arrest Wimpy for misleading an officer. Yet Wimpy is able to convince the lawmen to not arrest him by inviting them to a duck dinner over at his place as an apology, while leading them outside, much to their delight. Back inside the restaurant, Barnacle Bill explains his reason for visiting Popeye, telling him that he may have found the secret location of Plunder Island and that if they joined forces, they could get their hands on all manners of priceless pirate loot, from gold to rubies to pearls the size of eggs. Popeye eagerly accepts the invite and teams up with Bill Barnacle, having become bored with the simple life of a restaurant owner and craves to go out to sea once more. Back outside, Wimpy has fled from the officers after telling them that they should bring the duck, much to their anger, and they go in hot pursuit of the moocher.
The next day, Popeye and Salty returned from a fun but violent night on the harbor where they enjoyed all manner of drinks and fights, defeating some 27 bruisers over at Mike's Place in a single night. When they returned to Popeye's restaurant, Olive told them that the police had arrived with the intention of arresting Popeye and Bill for their destructive antics the previous night. Popeye and Bill gladly turned themselves in, but not without making several sarcastic quips. Once they were placed in their jail cell, Popeye noticed a strange fellow quivering in the corner. Bill Barnacle realized that the fellow was none other than Professor Cringly, his "key" to finding Plunder Island, whom he had found at sea before reuniting with Popeye. Bill then questioned Cringly as to why he was in jail, only for the scaredy Professor to confess that he purposely got himself arrested by throwing a brick through a window; he had done so believing that he would be safer in police custody while Bill Barnacle was out. Popeye proceeded to interrupt their conversation by asking if they should escape now that it was dark, but Cringly quickly begged to stay, claiming that his old mistress, none other than the wicked Sea Hag, had found him and was in the port, having supposedly seen her ship through a window. Popeye however was quick to dismiss Cringly's notions. Having past experience with the old witch, Popeye knew that she would never dock at any port in the civilized parts of the world. The trio then broke out of their prison cell with relative ease by breaking down the wall, and made their way back to Popeye's restaurant for rest and to see if anyone else had claimed to have seen the Sea Hag.
Unbeknownst to the adventurous group, the Sea Hag had been keeping track of them all from the beginning while aboard her ship, where she and her first mate Skom plan their next move to take back Professor Cringly. As Skom gives the latest details on Cringly's whereabouts to the Hag, she decides to take direct action and has Skom stay with the ship whilst she heads to port, despite Skom's protest that he should accompany her. The Sea Hag rejects his notions, claiming that she needs no guards, but she will not go alone, as her mightiest slave will be accompanying her to make sure that no one stands in her way. For this slave is a creature so terrible that even Skom would be frozen with fear at mere sight of it.
Back at Popeye's restaurant, Popeye escorts Cringly to his room for the night while he and Bill plan their voyage. They are soon joined by Wimpy, who politely introduces himself to Bill in hopes of mooching a hamburger meal from him, but Popeye intervenes and has Wimpy stay Cringly for the night to help him get to sleep, doing so by telling the scaredy Professor bedtime stories, which only serve to make him more unnerved. Meanwhile, Popeye and Bill discuss what to do about the Sea Hag with Popeye mentioning his last encounter with her years earlier. However, their discussion is cut short when they see a towering, ghostly creature staring at them from the restaurant's doorway, much to their horror. They then proceed to go after the beast, but it quickly disappears.
The two remain befuddled and horrified as they recall its unnerving appearance, which reawakens unpleasant memories within the two sailors: one of the darkest moments in their youth was when they were sailing together aboard dear old Mary Ann, and they recall the events of that dark night 20 years past. On that fateful night, their ship began rigging in an ominous and unusual tone, not unlike the sound of bones and skeletons moving, when suddenly the moon became blood red. The horrified sailors could only look on in shock as they saw numerous indescribable beasts clinging to the side of the Mary Ann, led by a sinister being that left the helpless youths paralyzed. The next morning, the duo and their skipper awoke to find five of the crew missing with no trace of them left behind. All that was known was that their frightening encounter aboard the "Ol' Mary Ann" would forever remind them of the all-true horrors and evil spirits that exist within the seas.
Reminiscing no more, the duo decide to confront their fears and find the ghostly creature, who strangely reminds them of the evil beasts that attacked the Mary Ann so long ago. They then see a very disturbed Cringly walking out of the restaurant, muttering to himself about the moon and sensing that "one of them is near", while seemingly being compelled to walk into the sea. He is stopped by Popeye and Bill, who call on Wimpy to take Cringly back to bed for his own good. They are unaware that the Sea Hag's glare is indeed upon them as she watches their every move, waiting for her chance to strike.
Back inside, Wimpy tells Cringly the story of The Woolly Worm and the Ladybug, which ends with the Woolly Worm scaring the Ladybug with a ghastly "BOO!", which frightens Cringly so much that he breaks through the roof and goes up a tree. As Popeye scolds Wimpy for his goof, the Professor is seen staring into the sea, where he catches the sight of the Red Moon, which is then followed by that of of the Sea Hag's cursed ship the Black Barnacle. As this causes Cringly to shout out in terror, Popeye and Bill run outside and behold the cursed sight themselves, while hearing the eerie cackle of the Hag. With tensions high, the duo realize that the night will be a very challenging one indeed.
A loud cackle then erupts from the dark alleys of the port as the Sea Hag makes her entrance with sinister bravado while swearing to tear the skin off the two sailors and nail them to her mast if they do not stay out of her way. The old witch then runs off into the alley and calls forth her beast, directing it to capture Cringly while she keeps the sailors busy. The heroic duo go in pursuit of the old witch, just as she had planned, and are led on a wild goose chase through the alleys of the port. Meanwhile, Wimpy continues trying to calm Cringly with the more relaxing fable of Little Tommy Cod and Big Brother Halibut, but the story comes to an abrupt end as Wimpy and Cringly become frozen with fear at the sight of the Sea Hag's beastly minion, causing the Professor to let out a chilling scream. Sadly, by the time Popeye and Salty realize they are being led astray in order to leave Cringly unprotected, the scream has already reached their ears and, by the time they get back, Cringly is already gone, having been dragged back into the sea by the mysterious creature. The duo instead come upon a passed-out Wimpy and attempt to revive him with a drink of water, only for their "unconscious" friend to tell them that a hamburger would be needed to revive him, much to their annoyance. With Cringly gone, Salty bemoans the fact that they would never find Plunder Island, their only link to it lost, but adds that they have to get him back somehow. Popeye then stares angrily into the sea and exclaims that the Sea Hag is still out there somewhere, laughing at them, but that somehow they will find her and give her what she deserves. This clearly does not faze the sinister Hag though, as her giddy and malicious cackles can still be heard from across the sea. The two sailors are left to spend the rest of the night planning their next course of action.
The next morning, in Popeye's restaurant, the sailor duo meet up with Captain Hull and request the use of his large but fast ship in order to pursue the Sea Hag, promising him a portion of Plunder Island's treasures as payment for his services. However, the old captain is none too eager to confront the infamous Sea Hag. Luckily, Salty is able to persuade Hull into helping them by reminding him of all the gold and "pearls the size of pelican eggs" that reside on Plunder Island. With this greedy spur as motivation, Hull agrees to help, adding that they will be doing the world a favor by taking down the Sea Hag. He notes that, before they can sail, the duo will need to provide him with a crew and the necessary supplies for the long voyage, to which they agree. The two then begin preparations, with Popeye setting out to collect provisions and a few key crew members, while Salty collects fresh water for the casks and recruits the toughest and most dangerous sailors around. Popeye's first choice for his crew is none other than his sweetheart, Olive Oyl, to keep him company on those moonlit nights, but his romantic plans are spoiled when Olive demands a female chaperone so as not to be the only female aboard a ship full of raunchy sailors. Despite Popeye's protests, he has to comply and proceeds to find a chaperone for Olive, picking her friend Miss Sniddle who happily agrees to join the crew thanks to her love of the sea. Popeye next pays a visit to the Rough House Cafe to see his old friend and favorite fry cook, Rough House, and asks him to be the chef aboard his ship. However, Rough House requests that he too be given a portion of the Sea Hag's treasure for his services, to which Popeye happily agrees. As the word "treasure" escapes their lips, George W. Geezil overhears and quickly arrives on the scene graciously offering his services as a shoe cobbler (or "shoe gobbler", as he calls it), willing to fix any shoes aboard the ship. Popeye sees no harm in Geezil's selfless offer and lets him join the crew as the "shoe gobbler", much to his delight.
Later, at 3:30PM sharp, the newly-formed crew of misfit heroes and tough-as-nails sailors finally gather at Captain Hull's ship with provisions accounted for and ready to set sail, but before they do, Popeye is approached by a mysterious stranger in a formal suit and fedora who introduces himself as G.B. Gritmore, who knows about Popeye's seafaring operation and intentions of going after the Sea Hag and her crew, further revealing that he is a secret agent in service to three nations that also want the powerful menace known as the Sea Hag to be dealt with once and for all. Since it is his job to run the old witch down, the agent asks Popeye to let him bunk aboard the ship as well, to which Popeye complies as long as Gritmore is a brave fellow with "intestimal fortnitude". With everything ready, Captain Hull orders the crew to hoist anchor and set sail, and begin their pursuit of the Sea Hag. Elsewhere, a petrified Cringly is locked away in the brig of the Sea Hag's ship with only the towering beast to keep him company, leaving the Professor completely paralyzed with fear, the only words to escape his lips being "The Goon! The horrible Goon!".
As the hours pass by, Rough House and Geezil become jovial, having a hearty good laugh as they realize that they are far away from their common mooching foe, Wimpy. Joyfully expressing their hatred and contempt for the eternal moocher, they laugh happily at the thought of finally having him out of their lives after so long. Just then, a sailor approaches Captain Hull and reports that there is a stowaway hiding in the sail locker. As he brings out the stowaway, Popeye and Olive are shocked to see that it is none other than Wimpy. Popeye then confronts him, having told him that he could not come along, however, Wimpy pays him no mind and sings a few verses from "Dead Man's Chest". As Geezil and Rough House bask in their merriment, they start quoting Wimpy's most infamous catchphrase in a mocking tone; "Come up to the house some time for a duck dinner-" only for Wimpy to arrive and finish their sentence with "You bring the ducks", much to their surprise and disgust. A furious Geezil goes into a blind rage and asks why Wimpy is there. As his anger grows, Geezil decides to jump overboard and drown himself in a fit of pure rage, no longer being able to stand Wimpy's presence. A frightened Olive begs for someone to save Geezil from his suicide attempt but, as Popeye prepares to jump into the water, Rough House beats him to it and jumps in after Geezil. Salty then stops Popeye from jumping, telling him that Rough House would take care of the rescue. Popeye then calls out to Rough House and asks him to stop Geezil before its too late, but the enraged cook reveals that he had also jumped to drown himself, choosing death before months at sea with Wimpy. Popeye and Salty decide to save the suicidal duo from their own blind fury, despite their protests. Elsewhere, the Sea Hag confronts a dejected Cringly, tormenting him as she reasserts that no one will save him and soon he will be returning to Plunder Island to face her full wrath.