The Land Before Time VI: The Secret of Saurus Rock is a 1998 American direct-to-video animated adventure musical film and the sixth film in The Land Before Time series. The plot focuses on main character Littlefoot's admiration of a heroic but reclusive Diplodocus named Doc, whom he believes to be a legendary hero dubbed "The Lone Dinosaur". Despite being largely overlooked by the critics, and receiving mostly mixed reviews, the movie garnered a Young Artist Award for voice actress Aria Noelle Curzon (Ducky) in 2002.
The film begins with Grandpa Longneck telling the children a story theorizing on the creation of the world. This is followed by a legend involving the residents of the Great Valley, a number of generations before, and how one day, an extremely ferocious Sharptooth attacked them, but was ultimately defeated by the legendary Lone Dinosaur; a Longneck who was known to protect societies by disarming Sharpteeth with his whip-like tail, but who preferred to live in solitude. Grandpa Longneck continues that some time later, a large rock emerged from the ground, resembling a long neck and bearing life-sized Sharptooth teeth encircled around its neck, which supposedly came from the Sharptooth the Lone Dinosaur defeated. The monolith was named "Saurus Rock", and a legend was spread that bad luck would descend upon the valley if the monolith were ever damaged.
The next day, the children are playing, when Littlefoot accidentally slips off of a rotten log. Before he hits the ground, he is caught by a strange longneck (Diplodocus) who introduces himself only as "Doc" and gives no knowledge of his history. Littlefoot is intrigued by the newcomer, especially upon discovering that one of his eyes bears a scar similar to one the Lone Dinosaur was supposed to have received from the Meanest Sharptooth, and when he displays prior knowledge of the Great Valley's topography. Littlefoot is quick to assume that Doc is the Lone Dinosaur, and informs his friends of this theory, narrating an apparently extemporaneous legend to support his assumption. Though Cera is quick to point out that the legend takes place several generations before their time, and the Lone Dinosaur would have passed away long ago, Littlefoot insists that he is right, and goes on to say that Saurus Rock likely resembles Doc to a match.
Cera's visiting niece and nephew, Dinah and Dana, two silent Threehorns speak gibberish, in which Ducky, translates for Cera, are intrigued by Littlefoot's theory, and set off on their own to find Saurus Rock. Upon discovering their absence, and knowing that her father will be furious that she didn't watch them carefully, Cera urges the others to help her find the twins. After narrowly escaping a sharptooth along the way, they reach Saurus Rock and discover that the twins have climbed to the top of the monolith. In the process of retrieving them, one of the teeth on the neck of the monolith is knocked off, and they recall the bit of the legend involving the onset of bad luck. The Allosaurus then returns and gives chase. As it is pursuing them, they hide in a fallen log, which is thrown by the Sharptooth towards a gorge, where it becomes suspended between each side of the canyon. They carefully break out and creep to the other side, but the Sharptooth attempts to follow them across the gorge. The rotten log breaks under its weight, sending it plummeting into the ravine.
When they get home, Cera is confronted by her father, who sternly scolds her for not being watchful of the twins. Over the next few days, ill fortunes ranging from the water hole drying up to a vicious tornado plaguing the valley. The adults blame Doc, in whose wake the misfortunes have apparently come. Littlefoot is convinced that the accident at Saurus Rock is responsible for the misfortunes, and eager to redeem himself and prevent Doc from being banished from the valley, he retraces his steps back to the canyon. He walks down protruding rocks on the cliffside and approaches the unconscious Sharptooth, but as he attempts to extract a tooth from inside its mouth, to replace the broken one, the Sharptooth wakes up and rises to its feet. Littlefoot jumps out of its mouth and flees. H escapes it, before he runs into a large T. rex that resembles the Meanest Sharptooth from the legend attacks him. Before he is eaten, his grandfather shows up and saves him. The Allosaurus then enters the fray, and the T. rex knocks down Grandpa Longneck, but then Doc arrives and saves him from the sharpteeth. The two Longnecks combine their efforts and imprison the Sharptooth in a landslide mound.
Littlefoot and his friends then retreive a tooth and repair the monolith, while Doc declares his departure, assuring Littlefoot that he already has a hero on whom to depend - his grandfather. Littlefoot later creates a legend of his own based on this new paradigm, portraying his grandfather as a savior, "The Great Dinosaur".
The Land Before Time VI: The Secret of Saurus Rock marked the first of four films in which Thomas Dekker provided the character Littlefoot's speaking and singing voice. He had previously provided Littlefoot's singing voice in The Land Before Time V: The Mysterious Island. This is the only film in the series in which Jeff Bennett provides the character Spike's voice in place of Rob Paulsen. It is also one of four films in which John Ingle does not serve as the narrator, as this film is narrated by Kenneth Mars. In this film, Danny Mann voices the Allosaurus. The Tyrannosaurus in the movie are not voiced by a voice actor; they use stock sounds from real animals, though with altered pitches.
- Kenneth Mars as Grandpa Longneck and the narrator.
- Thomas Dekker as Littlefoot
- Anndi McAfee as Cera
- Aria Curzon as Ducky
- Jeff Bennett as Petrie/Spike
- Kris Kristofferson as Doc
- Miriam Flynn as Grandma Longneck
- John Ingle as Cera's father
- Nancy Cartwright as Dana
- Sandy Fox as Dinah
- Danny Mann as Allosaurus
- This is the third film in which Cera cries, and the fourth film in which Littlefoot cries.
- "Bad Luck" is Spike's second song.
- This is the second film in which Grandpa Longneck got knocked over by a sharptooth when fighting with one. The first time happened in The Land Before Time II: The Great Valley Adventure when he was fighting Mama Sharptooth at a lake. In this film, the Canyon Sharptooth knocked him over by kicking him with his foot.
- This is the last Land Before Time movie animated with traditional cel animation. Future films and the TV series are animated with digital ink and paint.
- In the scene where the gang are jumping in the bubbling mud pit, it seems to be very deep, an example of this being when Dinah & Dana push Cera in). However, while they are singing "The Legend of the Lone Dinosaur", the mud pit appears to be shallow enough for them to walk across it.
- Some Land Before Time fans believe that Secret of Saurus Rock was originally supposed to be the final film in the Land Before Time series, due to small gap between VI and VII. It is unknown whether or not this is the case.
- If the Lone Dinosaur only comes when Sharpteeth enter the Great Valley, he should have come during The Great Valley Adventure, Invasion of the Tinysauruses, Journey of the Brave and the entire TV series. No Sharpteeth enter the Great Valley at any point in this film, however, so that part of the story is likely a myth.
- When Grandpa Longneck states "Our life here is a sheltered one. Perhaps we've forgotten how to greet unexpected guests." his coloration is that of Grandma Longneck's.
- When the Sharptooth drools on Cera, she mentions if it’s gonna rain and this is the only time it’s mentioned as rain even though everyone’s always calling it sky water.
- This is the first film in which Spike is voiced by Jeff Bennett instead of Rob Paulsen.