A fire-breathing dragon wanders onto the Lost City plaza and shoots flames into the central cave. The Sleestak within are forced back from the entrance by the bursts of flame and its resulting smoke. Big Alice detects the intruder but too is driven away by the dragon beast's fire breath. Will and Uncle Jack happen to be travelling in the jungle nearby, where they stand in awe to witness the event. Jack likens the monster to a "20-ton blow torch"; Will notes how it smells like an old coal stove. Jack shows concern that if Big Alice is kept away from her own territory, she will likely be terrorizing the entire jungle. Will also points out the trouble that the Sleestak are in when he and Jack witness the beast again throwing his fire-breath into the Sleestaks' tunnels. Jack then makes up his mind and decides that "that character has got to go". Will notes that they can outrun the sluggish beast, but may have a hard time dealing with the monster's blow torch. Jack points out that any blow torch must eventually run out of fuel; at that very moment, the beast's fire-breath becomes exhausted. Uncle Jack then proposes that they could entice the now-fireless beast into the jungle where Grumpy could take care of it. Unfortunately, when Will approaches the monster, calling out to get its attention, the angry dragon lashes its tail, striking Will in the legs, knocking him down. Jack rushes to his nephew's side to help him hobble off the plaza's pavement and into the jungle where they can safely examine the wound. Uncle Jack inspect's Will's wound beneath the torn pant leg, and after deciding it is fairly serious, helps Will back to the Temple.

Holly and Cha-Ka take a break from house-cleaning as soon as they see Will hobble in with the gash on his leg. Will informs them that they just had a run-in with a fire-spouting dinosaur outside the Lost City. While Uncle Jack describes the fire-spitting beast to an inquisitive Cha-Ka, Holly shows concern over the pain her brother must be in. Will says that his injury feels like "1000 porcupine needles". Uncle Jack assumes that the beast's tail spikes must be poisonous, so he volunteers to prepare a hot compress that will help to draw out the toxin. Holly feels pity for her wounded brother, but Will is simply thankful that he and Jack weren't "barbecued" alive.

Deep in the tunnels of the Lost City, the Sleestak Leader visits Enik working in the time doorway chamber. The Leader blames the presence of the troublesome fire-breathing creature on the Marshalls, and urges that he and the Altrusian consult the Voice of Wisdom. In the Library of Skulls, the Voice of Wisdom informs the Sleestak Leader that the humans must rid the valley of the fire creature or "face the consequences". The Voice goes on to note that Will is sick, poisoned by the creature's tail; Enik is to tell the Marshalls that in order to obtain the cure, they must first get rid of the troublesome fire-creature. In ridding the valley of the creature, the Voice of Wisdom predicts that the Marshalls will "get rid of themselves".

The Marshalls tend to Will back in the Temple; Cha-Ka brings him a large bowl of soup, Will, however, is tired and weak, and would rather sleep to dream of home. Uncle Jack recommends that his nephew sleep, when suddenly Enik arrives, demanding Jack's attention. The Altrusian is aware of Will's illness, and informs Jack that Will must receive the cure by nightfall or else fall asleep "until the end of time". Enik claims to be the only one who knows the cure, and insists that the Marshalls must first earn it by driving the flame creature from the valley. Uncle Jack argues that performing such a task by nightfall is impossible -- Tyrannosaurs run from it, it has a wicked tail and teeth, and it "throws off more heat than a volcano". Enik is unyielding in his offer, simply replying that he will return with the cure at nightfall only if the Marshalls are successful.

Weakening Will tries to get up to help his family deal with "Torchy", but Holly tells him to stay still to minimize the circulation of the poison. Uncle Jack leads Holly and Cha-Ka out on their mission to get rid of "Torchy"; he foolishly leaves half-conscious, delirious Will with no more than a wet handkerchief to cool his forehead and the simplistic command "stay awake".

As Jack leads Holly and Cha-Ka through the jungle to hunt Torchy, he points out that while the beast has many physical advantages, they can still defeat it by using their superior intelligence. Jack realizes that they must find a place to trap the creature; then they will locate Torchy and figure out how to lure him there. He proposes Echo Canyon, so the group heads over to it.

At the canyon, Jack finds its high walls and narrow entrance a suitable trap for Torchy. He notices a huge boulder very conveniently located above the narrow pass; he proposes that they use a large bamboo pole nearby to dislodge it, where it will fall and block Torchy's exit once the beast has been enticed inside. Jack assumes that like other dinosaurs, Torchy is very territorial; it will attempt to fight off other members of its species that intrude upon its turf. Holly thinks that her uncle is joking when he says they already have such an intruder, but before Jack can explain, they flee from the threat of Spike who is grazing near the jungle's edge.

Uncle Jack leads Holly and Cha-Ka to an outcropping of huge mica sheets. He explains that individual sheets are transparent, but stacked sheets are reflective; he proposes that they build a gigantic mirror. Jack asks Holly and Cha-Ka to cut several sheets of the mica, as well as gather bamboo poles for the mirror frame; he will seek out Torchy and attempt to lure him over to Echo Canyon. When Holly immediately questions how Jack is going to accomplish such a feat, her uncle plans to entice the beast with its favorite smell. Uncle Jack relates to Holly that when he and Will ran into Torchy that morning, Will noted that the beast smelled like a coal stove; Jack has a hunch that coal is the main staple of Torchy's diet, and that coal would work as the perfect bait. As Jack sets out to find Torchy, he reminds Holly and Cha-Ka to meet him at the canyon with the mirror materials.

While Will fights to stay awake back in the Temple, Uncle Jack arrives at a jungle cave and begins mining coal with a hatchet. Meanwhile, as Holly and Cha-Ka gather the mica for the mirror, they both admit that they still don't understand how Jack is going to lure Torchy into their trap. Upon hearing Grumpy's roar, Holly urges Cha-Ka to hurry, so they pick up the bamboo poles with mica sheets laid on them like a stretcher and begin their trek back to Echo Canyon. Luckily, Grumpy gets himself caught trying to run between two trees (yet another recycled animation scene), but the two keep dropping their end of the "stretcher" each time they are startled by the tyrannosaur's roar. While resting after "ditching" Grumpy, Cha-Ka notices Holly's reflection in the mica sheets, and makes a stupid joke that she looks "pretty, like Sleestak". They realize it will soon be nightfall, so they hastily continue on.

While Uncle Jack mines coal in the jungle cave, two Sleestak down a passage spot him and quietly approach. Luckily, the Sleestak Leader intervenes, commanding his Sleestak warriors to spare the human so that he may rid them of the fire creature. Out in the jungle, Jack locates Torchy and calls out to the beast to get its attention. He a tosses softball-sized chunk of coal toward the fire lizard, then starts leading the beast to the canyon by waving another chunk in his hand. Resting in the Temple, Will has nearly fallen asleep, but he is alerted by Grumpy roaring about in the nearby jungle. While Holly hurries Cha-Ka as they construct the giant mica mirror, Will cools his head with a wet handkerchief, struggling desperately to stay awake.

Uncle Jack's task of luring Torchy is depicted as absurdly simple; the event is turned into a farce as Jack tosses chunks of coal from behind his back, laughing as he playfully refers to the bait as "appetizers", "jellybeans", and "gumdrops". Just as Holly and Cha-Ka complete the mirror, they hear Torchy's roar approach, so they quickly climb up onto the ledge with the poised boulder. Jack is still goofing around, this time bowling the next chunk to the monster ("right down the alley... ha! strike!", he laughs). Back at the Lost City, the Sleestak Leader commands Enik to check up on the Marshall's progress, so the Altrusian heads out to their compound, replying that they have only until nightfall.

When Uncle Jack finally arrives at Echo Canyon, Torchy follows so soon after that he barely has time to empty the remaining coal from his sack. He manages to escape around a large rock along the bluff, where he climbs up to join Holly and Cha-Ka on the ledge. While Torchy feasts on the last bits of coal, the Marshalls quickly maneuver the large bamboo lever into position. Jack reaches above the boulder to yell into the entrance to the canyon; his voice reverberates within its walls, deceiving Torchy into believing that the family is trapped inside. Once Jack's thrown voice gets Torchy's attention over toward the canyon's pass, somehow the jumbled image from the sloppy collection of uneven, overlapping mica sheets succeeds in inciting the beast to charge. Promptly after Torchy crashes through the mirror, Jack, Holly and Cha-Ka pry the boulder loose; the huge stone breaks apart as it plugs off the canyon's only connection to the valley. With their mission accomplished, the Marshalls climb down from the ledge. Surveying the fallen boulder and demolished mirror, Jack reminds Holly and Cha-Ka that they only defeated Torchy by making him defeat himself. Holly believes the beast will be stuck there for a long time, but her uncle is hesitant to feel so confident. Dusk approaches, so they rush back to cure Will.

Meeting Enik back at the Temple courtyard, the Altrusian warns that Will risks eternal sleep unless the family has achieved their impossible task. Uncle Jack assures Enik that they have indeed rid the valley of the fire creature; they have trapped Torchy in Echo Canyon. When Jack demands that Enik keep his end of the bargain and reveal the cure, the Altrusian simply states that the victim should lie still and let the poison works its own way out. The Altrusian turns his head slightly and wanders off, leaving the Marshalls feeling conned into getting rid of Torchy. (Enik's behavior here is very questionable; though his race is weak in compassion, he only once before engaged in any form of intentional deception [Blackout], and in that case he was painfully reluctant to do so. Even during his violent first encounter with the Marshalls [The Stranger], he stated that "Altrusians are incapable of lying"; it is unfortunate that Enik's character has now eroded to such an extent). Holly vengefully hopes that their favor will backfire, and as they head inside to see Will, Torchy climbs over the rocks blocking the canyon.

The family rushes to Will's side, desperately trying to awaken him from eternal sleep, but they are soon in on Will's joke when he starts to crack a smile. More of that obnoxious moseying clarinet music from "The Repairman" plays as Will hops to his feet and claims that he feels good enough to dance and sing. Cha-Ka proposes that Will can now go fetch their firewood, but Will quickly makes the excuse that he "doesn't feel that good yet". After Holly expresses her worry for her brother and gives him a hug, Cha-Ka is at it again, this time begging Will to sing; the excited Paku hands to Will the sorriest excuse for a guitar or banjo (I'm not even sure which) that you've ever seen. Will fiddles for a moment with the stringless instrument, and to everyone's delight, sings a few lines of drivel.