An evolved dromaeosaurs dinosaur named Eno escapes from an underground world where the last remaining dinosaurs have taken refuge from humans. While he's being hunted by two predatory dinosaurs called the Diggers, Eno encounters fifteen-year-old Lauren Slayton. She's terrified and runs away, but leaves behind a cherished locket that her missing father had given her.
Lauren and Courtney get lost in the woods while searching for Lauren's locket, and they are chased by the Diggers until Eno fights off the deadly dinosaurs and saves the girls. Chris and Kit arrive to help them, and so does the mysterious Dr. Aikens who begins asking some suspicious sounding questions.
Eno gives Lauren back the locket from her father and she gives him the name 'Eno', but he becomes frightened and disappears into the woods. Lauren follows Eno but comes upon the Diggers and she heroically fends them off and keeps the vicious dinosaurs from harming other campers. Meanwhile, Nelson and Danielle find one of Eno's footprints and tell Dr. Aikens, who recruits them to spy on the counselors.
Lauren and Kit go to find Eno, but change their plans when a grizzly bear begins to stalk them. At the same time, Eno discovers that the Diggers have set up their headquarters in an abandoned coal mine, where they nearly trap him. Eno escapes and returns to his wilderness hideout in time to save Lauren and Kit from the fearsome grizzly. Back at camp, Courtney and Chris do battle with a skunk ... and lose.
Lauren hopes that a medicine man named Ten Bears (Kit's Uncle) may hold the secret to her father's disappearance and the arrival of the dinosaurs. But instead of offering help, Ten Bears warns them to stay away from the dinosaurs, which he calls the "Unktehi", a dangerous creature from Native mythology. Elsewhere, Eno has been trapped by poachers. Lauren and Kit distract the poachers and free him, but now Eno is afraid of humans and he turns on Lauren before escaping into the woods.
Lauren tries to befriend Eno by offering him some hot dogs which doesn't work. Later, she discovers that her father wrote The DinoSapien Theory about intelligent dinosaurs like Eno and the Diggers. Meanwhile, Eno is still hungry and encounters Courtney with a bowl of hot dogs in the woods. Little does she know, Danielle and Nelson have planted a "bug" on Courtney, and they overhear the name "Eno". The kids pass along this "secret password" to Dr. Aikens who becomes surprisingly intrigued.
Eno tries to communicate with Lauren but she can't understand him. Out in the Badlands, Ten Bears confronts the Diggers speaking his native Sioux, a language the dinosaurs understand. Back at camp, Nelson is feeling homesick. While helping Nelson, Lauren suddenly realizes what Eno was trying to tell her.
Eno discovers the destructive power of lightning and he sets out to harness it. His search for tools brings him into camp on the day of the Talent Show. Nearly discovered by Dr. Aikens, he takes cover. Lauren realizes she must smuggle him out of the camp and convinces Courtney to ham it up in the Talent Show to distract everyone. Safely back in the woods, Eno tests his "Lightning Collector". But we don't know why he has built it or what he wants to use it for.
While everyone goes on a camping trip, Dr. Aikens sets out on a hunt for Eno with a tranquilizer gun. The camping trip goes badly and tensions are running high between the counselors. The Diggers catch the scent of Dr. Aikens and stalk him, fascinated by his weapon. Lauren foils Dr. Aikens quest and believes Eno is safe for now ... except no one knows that the tranquilizer gun is now in the hands of the Diggers.
Just when Lauren discovers that Eno knows her missing father's name, the Diggers capture her and take her deep into the coal mines. Once she is discovered missing, Courtney recruits Nelson and Danielle to help guide Kit and Eno to the hidden entrance of the coal mine. Kit and Eno find Lauren but fall into the Diggers' trap. Eno tries to fight off the Diggers but the scuttle causes the mine to collapse and they don't all make it out on time.
While searching for Eno in the woods, Lauren and Kit are nearly attacked by the Diggers. They're saved at the last minute by a bright shaft of light which temporarily repels the evil dinosaurs, causing Lauren and Kit to wonder who their mysterious protector is. Meanwhile, Dr. Aikens steals Danielle and Nelson's prize from the scavenger hunt as he believes it's actual proof that dinosaurs are still alive.
Lauren decides to tell her mother about Eno to keep him from being captured by Dr. Aikens, or discovered by Nelson and Danielle. Courtney has her own solution to thwart off the kids curiousity. Kit takes Eno to the Badlands where he will be safe, but Eno runs away so he can be with Lauren. Chris finds out the hard way that Lauren was telling the truth about dinosaurs when he's captured by the Diggers.
Eno has caught a cold and without any human anti-bodies, he's in danger of dying. Lauren and Kit track him to the Badlands, and discover that Ten Bears is going to help them find a cure. Back at camp, Courtney breaks up a food fight but she loses Lauren's dinosaur journal. Everything Lauren knows about Eno is in the journal and now it has fallen into dangerous hands.
Dr. Aikens has teamed up with the poachers to track down Eno. Lauren and Kit are hiding Eno and call Chris and Courtney for help. But Courtney and Chris get intercepted by the Diggers. After a wild chase, Dr. Aikens suceeds in capturing Eno. Little does Aikens know who is hiding in the back of his truck.
Dr. Aikens wants to use Eno as bait to destroy the dinosaurs as they emerge from their caves in the Badlands. Lauren is able to locate Eno with Nelson and Danielle's help. Undeterred, Dr. Aikens continues to stuff dynamite into the caves, but the Diggers arrive and chase him off. When a bolt of lightning strikes, the Thunderbird myth Ten Bears had foretold becomes a reality. Will this make Lauren and Eno's dreams come true?