The Earthlings split up to search for food and Fitzhugh goes to a local pier. A fisherman, Talf Ekorb, brings his catch to his dockside shack, leaving a discarded piece of shrimp. Fitzhugh goes over to pick it up, while Talf's wife, Osla, and his deaf son Dal, come over to join him. Talf tells his wife that they should be able to get credit because of the of his catch, the best he's had month. Osla says that she'll help and sends Dal to look around for shells. Dal sees Fitzhugh's tracks in some sand and follows them to where the Earthling is trying to drag the shrimp away. When Fitzhugh sees the boy approaching, he tries to hide behind a crate. Dal tries to grab him and Fitzhugh pricks him with a discarded fishing hook and then runs off.
The bank creditor, Mr. Derg, drives up and Talf suggests that Osla take Dal home. Once she leaves to find her son, Dreg comes over and informs Talf that he has two weeks to pay off his loan to the bank. Talf complains that he's had no business for five weeks, but Derg tells him that the decision is out of his hands. Meanwhile, Dal runs up and tries to sign that he saw a little person. Talf can't make it out and sends him home with Osla.
Fitzhugh gets back to the Spindrift and tells Betty and Valerie how he heroically fought off a giant boy while gathering seafood. The women want to go back and get the food. When Fitzhugh refuses, they ignore him and go off on their own. The others return a few minutes later and Fitzhugh tells them where the women left, and the three men go off to get them, leaving Barry with Fitzhugh.
At the docks, Betty and Valerie see Dal playing with a toy boat. He puts it down and takes a lobster out of its cage. The boy notices some large conch shells and goes over to examine them, and Betty inadvertently knocks over a board. Dal ignores her and the women realize that Dal is deaf. The lobster approaches them and Val sprains her ankle, tangling it in a discarded net. Steve and the others arrive, and Dal comes back. Mark and Dan go to distract him while Steve untangles Valerie and carries her into a nearby shell with Betty.
When Dal picks up the shell containing the three Earthlings, Dan and Mark try to distract him. He doesn't hear them and goes to the shack, where Talf plays the "shell game" with his son. Talf concedes that Dal has the bigger shell and goes back to their house, and Dan and Mark follow them.
When father and son get home, Osla puts the shell upon a table and talks to her husband about their son's future. Talf admits that they don't have the resources to send Dal to a school for the deaf. He tells Osla that they're out of money and the bank will foreclose in two weeks. When Dal gestures to play, Osla tells him to clean out the shell and goes outside with Talf so they can talk privately. Dal uses a wire brush to scrape out the inside of the shell, and Steve is forced to shove it out. Dal realizes something is inside and dumps the three Earthlings out.
Dal gets his parents, who figure they can turn in the little people for a reward. Steve insists that they're no danger to the planet but Talf believes the government propaganda. Meanwhile, Dal signs to Osla that he saw a different Earthling earlier, and he fled into the woods. Talf figures that Dal can track him because of his keen eyesight, and they put the Earthlings in the shell and take it with them as they track Fitzhugh.
Dan and Mark run to Spindrift to warn Fitzhugh and Barry, but a weasel attacks them. The two men duck into a gopher hole and they try to fend the animal off as it tries to dig its way in.
The Ebroks find Spindrift deep in the woods, pick it up, and take it back to the house.
Dan and Mark make a torch drive the weasel off, and then run to the campsite. They're relieved to discover that Barry and Fitzhugh hid outside the ship when Steve warned them by radio. They contact Steve, who has been put in Spindrift with the women, and then set off to rescue their friends.
The Ebroks lock Spindrift in a closet and Talf tells Osla that he's going to City Hall to find out how he can collect the ward. Once he leaves, Osla tells Dal that he'll soon be going to the school for the dead. Steve, listening in, calls Mark on the radio and asks if he could create a hearing aid for the giant boy. Once he does, Steve figures they can trade it for their freedom, but first they have to trade Dan and Mark for Betty and Valerie. As Dan and Mark prepare to go in to contact Osla, Fitzhugh warn against it but Dan tells him to stay with Barry and stand watch.
Dan and Mark slip in beneath the door and get Osla's attention, and ask her to open the closet door so Steve can talk with her. They insist that they want to help dal and Osla reluctantly opens the door. Steve assures her that they can help Dal when giant scientists have failed because of their advanced technology and their small First he wants to trade the women for the men, so that Betty and Valerie can get to safety and Mark and Dan can work on the hearing aid using the ship's equipment. Then Steve wants to trade the hearing aid for their freedom. Osla agrees to trade the men for the women but says that she'll have to talk over the other trade with Talf.
Fitzhugh and Barry are waiting outside when Valerie and Betty run out, while Mark works on the hearing aid. Talf walks down the street and Mark tries to finish the hearing aid so he can demonstrate it to Osla before her husband arrives. He succeeds and gives it to Osla, who applies it to Dal's ear. It doesn't work and Osla tells Talf about Steve's offer. Furious that they got their son's hopes up, Talf gives the hearing aid back to the Earthlings and accuses them of trying to trick his wife. Steve and Mark insist that their offer was sincere.
Once Talf locks them back in the closet, Mark realizes that the unit didn't have enough amplification for a giant- ear. Steve suggests that they use a shell, remembering how the one they were in amplified the outside sound. Mark calls to Talk and asks him to get one the shells, but Talf refuses to get his son's hopes up again. Steve points out that he can make money from the patent on the hearing aid then from the reward, but Talf refuses to listen and leaves them alone.
With time running out before Talf turns them in, Steve calls Fitzhugh and has him and the others lure Talf out. Once the giant husband goes outside, Steve calls to Osla and asks her to give them one final chance. She reluctantly agrees and puts Steve and Mark on the table with the shells.
Outside, the Earthlings try to distract Talf but he manages to capture Barry and takes him inside. Meanwhile, Mark climbs inside the shell and attaches the hearing aid to the interior. Talf comes in with Barry and puts him with the others. Steve tells Talf that they've got the hearing aid working, but Talf refuses to let them try. While Osla argues with him, Dal picks up the hearing aid shell on his own and puts it to his head, and then gestures to his parents that he can hear. Talf thanks the Earthlings but admits that since he told the government about them, no one will believe he built the hearing aid on his own.
As Talf places Steve and Mark with Dan and Barry, Osla tells her son that she'll talk to Talf about honoring their deal. Once she goes outside with Talf, Dal picks up Spindrift and carries it out. Talf realizes that his son has left and goes after him. Fitzhugh and the women shove a tin can under his feet, tripping him. He tries to capture them, but Osla runs up and tells her husband to let them go. She points out that the government can't blame them if Dal took the ship on his own, and Talf lets the three Earthlings go.
Dal takes Spindrift out into a different part of the woods, sets it down, and covers it over with brush. Steve and the others come out and thank Dal for his help as he leaves, confident that he won't betray them after he helped them.