It is Barry's birthday and the group at camp prepare a surprise party comprised of a giant candle and fruit, bells, etc. Barry was taken by Fitzhugh on a phony mission to get a pair of shoelaces Fitz said he found--Mark joking this is not a good cover. Steve notes Barry's moping around; Betty thinks it is because Barry believes they forgot his birthday. Fitzhugh calls and Steve answers from the cockpit. He tells him Barry collapsed just as two giant police pursued them with nets. (This sequence was used as one of the last LAND OF THE GIANTS promos with a narrator saying, "They're a billion light years from home on a strange LAND OF THE GIANTS.") Steve and Dan come running as Barry goes into spasms of pain--alerting the giants who think they heard something.


Steve has Barry bite on a handkerchief until the giants pass the area. Dan carries the boy back to the ship where Betty, lead into the ship by Steve so Barry cannot hear their discussion, tells them the medical book explains the symptoms as appendicitis. Mark and Dan use the compressor to make cold packs. Fitz tells Steve he does not want pilot's reassurances; he wants to know what he will do about the boy. Steve throws the pilot manual in frustration. Steve tells him not to panic--but later, Barry gets worse--it is acute and Betty tells them they have to face it. Without an operation, Barry will die. The men elect Betty to do the operation--she is the medical and first aide expert among them. Steve tells them he will do it when Betty gets upset. They must first get some ether. Fitzhugh refuses to stay behind when the men plan and go toward the hospital. The four hide at a fire hydrant. A boy unloading a truck (Oggo) spots Fitzhugh but Fitzhugh runs back to camp while the other three men get into a crate the boy carries into the hospital. They see an operating room but the doors are closed and worse: they are menaced by the sweeping mop of a giant janitor called Zacor!


The janitor puts a tray down which Mark and Steve search--and are forced to hide in when he returns. They had opened a bottle but the head doctor, Dr. Brule returns, blaming the janitor for not corking it. The janitor wants to drop the tray down the incinerator but Brule orders him to do it later. Dan rejoins the two and they race into the operating room, the doors being left open by Brule this time. They climb up to the desk top while the doors remain open--they are too big for them to close again. They find ether. At Spindrift, Fitzhugh gives Barry all his money in order to give him the will to survive but Barry says he cannot take it. Whimpering, Chipper lays under Barry's makeshift bed outside. Betty tells Val that a call from them could put the men in danger so they will wait to tell them Barry is getting worse. Brule discovers the trio of men and when he hears their dilemma, he offers to help. Steve tells him Barry is a boy about 11. Brule tells them he will help only if Fitz can translate a German medical book which he recovered from an Earth ship which crashed years ago--everyone on board dead. Mark, at first, doubted Brule's honesty but the doctor closed the doors and got some equipment for them to use. Fitzhugh will start by translating the chapter on appendicitis first (Kurt Krasnar really knowing German). The janitor, jealous of the doctor and just a working stiff (and seeming to be a Brooklyn-ite), calls the police. When Brule leaves again--to get some tiny surgeon's kit which he also found on the former spacecraft, the janitor tries to grab the three Earth men!


Dan uses a scalpel to stab the janitor's hand, then the three knock over the bottle of ether to get the janitor out of the room. Brule returns with ether in tiny bottles in order for them to do the operation in the forest. He takes the trio out of the room in his medical bag. The police don't believe Zacor--they cannot accuse a prominent doctor without proof and they leave. With Brule's help, Dan and Steve form a windbreaker out of leaves, twigs, and stems. On the way to Brule, Val tells Fitz they do not trust Brule, the trust Steve, Dan, and Mark. She also makes Fitzhugh feel better by telling him that he is the only one who can translate the German book the time of which it may take seems to Fitzhugh in his own words to be "from now to DOOMSDAY." However, Fitzhugh says he would translate a whole library to help Barry. Mark puts Barry to sleep with the ether while Dan and Fitzhugh go to a tree to keep watch. The janitor arrives and nearly gets Chipper. Dan races out to get the dog and takes him back to the tree undercover. The giant shines his flashlight toward the tree--and Fitz, Dan, and Chipper.


The giant leaves, now holding Dan's dropped radio. Steve is doing the operation as Brule watches over through a magnifying glass. Steve needs cotton from a nervous Betty and has to remind her twice. He uses it to stop the bleeding, then he begins to suture. Steve feels he is not doing it right but Brule urges him on to finish and checks Barry with his giant stethoscope. Brule tells them, "You are amazing creature." Steve smiles, "More amazed than amazing right now." They cover Barry with giant leaves and try to lead the police away on a false trail using ether. The police shoot and wound Dr. Brule, then handcuff him around a tree.


Brule, points the callous guards and Zacor on a false trail, made even more plausible when Steve orders Dan and Mark to use the ether to make the trail go that way. Steve and Fitzhugh go to Brule who warns them off when Steve asks what they can for him. Fitz is forever grateful. Steve asks why he risked his career and life for them. Brule did it for oath he took to the doctor's ancient creed which no one knows from where it came. It is almost ignored by all these days. It is the doctor's Hippocratic Oath from Earth--to render help to all those who need it. Fitzhugh says, "I'm sorry, doctor," and starts to raise the German book up to him. Brule tells him to keep it--the day may yet come when he will need Fitzhugh to translate it. Fitzhugh holds himself at Brule's disposal, sad. The next morning Steve brings Chipper to a recovered Barry, who wears a robe. Barry says, "You know, that doctor was a pretty good guy...for a giant." Steve corrects him, "That doctor was a pretty good guy." He pats Barry on the head.