Rat is rowing a boat while Long John Silver is using a periscope to look for ‘a treasure that leads to treasure’ referring to a compass that was dropped by Flint into the water in a wild pitch of rage never to be seen again. This compass will lead them to the treasure. Suddenly, Rat notices a shark. It knocks the boat sending Silver overboard, losing the map and compass. Rat throws him an oar to pull him in but it hits Silver on the head. As Rat gets a rubber ring, a strange creature carries Silver ashore. Rat rows to shore where Silver comes around. His rescuer is a merman. Silver can’t believe his eyes, having heard tales. Silver tells the merman he is looking for a special compass and asks if he knows of any treasures in these waters. The merman says he does but only has his mind set on only one treasure: a wife. He’s searched the seven seas and would give a royal treasure for a bride but none will have him. Silver comments for he could give the merman a wife: his own daughter, captured and refined: Jane, lying that she is his daughter, in return for a magic compass.
Ben Gunn secretly sees everything and tells Jim and his friends though the Squire doesn’t believe in mermen. Trelawney has built a bellows to keep himself cool but it doesn't work quite as planned.
That night, Jim tells Jane how everyone laughs at Ben. Jane thinks if Long John is looking for the compass then they should be too. Hearing a noise, Jim goes to investigate leaving Jane alone when suddenly she is grabbed by Silver. He takes her to Skeleton Island and tries to teach her to be ladylike ready for her husband, angering Jane. Rat slips that it is a merman. “You’re giving me away to a fish?” asks Jane. Silver replies that the merman is a prince and when she meets him, she will pretend she is Silver’s daughter. “This just gets better and better” exclaims Jane.
Long John and Rat try to put Jane in a dress but it isn’t suitable. As the two pirates leave to find something sturdier, Jane frees her ropes and sneaks past the two pirates, overhearing about the magic compass and instead returns to captivity.
Back at the campsite, Livesey, Smollett and Trelawney are preparing to find Jane. The doctor says she’s probably just lost. The sceptic Jim says Jane knows the island better than Ben and they must get to Skeleton Island because she might at this moment be getting tortured.
Silver is now teaching Jane how to improve her posture by balancing a book on her head. This is followed by complementing lessons.
Livesey, Smollett and Trelawney head out to find Jane leaving Jim with a horn to blow into in case he hears anything. The lad throws the horn into the doctor’s bag and gets out a bottle of ether planning to rescue Jane. He sails on a raft to Skeleton Island and knocks out Silver and Rat with the ether. Jim wakes Jane up. However, she refuses to go, saying she’ll meet the merman prince tomorrow and get the magic compass. She tries to scream so Jim starts to smoother her with a handkerchief covered with the ether. However, she moves the handkerchief onto Jim, knocking the lad out.
Next morning, Silver takes Jane wearing her dress to meet Prince Theodorick (the merman prince). Silver introduces Jane to Theodorick and asks for the compass but the merman can’t marry her, as she’s a stranger to him. Silver suggests going along with her to get to know one another. Theodorick gives Jane his pendant, enabling her to breathe underwater. Jim comes around and sees Jane in the sea with Theodorick. Jim escapes on his raft, intending to get help, spotted by Rat.
Underwater, Jane is having fun being able to breathe underwater.
Back at the campsite, no one believes Jim except Ben, who knows how to rescue Jane. Jim and Ben find a diving suit. Ben tells Jim to put it on, as he’s going diving. Jim asks about air so the duo steal the bellows.
On the longboat, Silver is using his periscope to look underwater. Rat notices Jim and Ben on the raft and tells Silver “Master! Hawkins, sir, he…” only for Long John to reply “Got away, yes, yes, you told me” unaware Jim and Ben have floated past.
In his diving suit, Jim goes under the water while Ben pumps on the bellows giving the boy oxygen. Rat tells Silver to no avail.
Under the water, Theodorick realises Jane is after the treasure and not interested in him and swims off following a rude remark from Jane. She swims after him but is grabbed by Jim. She fights with him and the pendant comes off her neck. She swims to grab it and the two youngsters then head up to the surface. Jane is cross with Jim as everything was going fine until he showed up before climbing onto the raft. Jim asks Ben to give him a hand but discovers Silver is on the raft, telling Jim that Ben is ashore.
On the shore, Ben shouts they’ve found the compass: it’s around Jane’s neck. Jane opens the pendant and discovers it’s a compass. She and Silver then fight over it, causing the pendant to fall into the water. Theodorick arrives a throws a chest onto the raft. Jane jumps into the water and Theodorick accompanies her and Jim to shore.
On the shore, Theodorick announces he is returning to the sea. Jane apologises to him for being rude but he tells her she was right: he was clumsy and has bad breathe but no one under water notices that. Jane tells him it’s what’s inside that’s more important. Jane kisses him and tells him that she is impressed that Theodorick saved her despite saying mean things to him and hopes he’ll find his mer… princess. “You really think so?” asks Theodorick before swimming off into the sunset. Jane cries. Jim tells her they lost the compass. She says it’s all right, at least Theodorick will find his treasure. “I would have settled for the compass” remarks Jim. “Oh Jim…” exclaims Jane as the two friends head ashore. Share this article with your friends