The Land Before Time All Grown Up is a 2019 theatrical animated film, directed by Davis Doi. The film will be released by Amblin Entertainment and Universal Pictures, it features anthropomorphic dinosaurs living in a fantasy-based version of prehistoric earth. The plot concerns Littlefoot who is a all grown teenage Longneck who travels back to the Great Valley on his own by his father, Bron, and his grandparents while the begin migrating with other longnecks. On his journey, he meets his old friends who are also grown up Chomper, a teenage Tyrannosaurus ; Ruby, a teenage Oviraptor; Spike and Tippy, two teenage Stegosaurs; Petrie, a teenage Pteranodon; Ducky, a teenage Saurolophus; and Cera, a teenage Triceratops. The film explores issues of Littlefoot and his friend travelling back to the Great Valley after being gone for years and are being tracked by a Gorgosaurus.
After leaving the Great Valley Littlefoot and his friends gone separate their ways with their folks while Chomper who has gone into the Mysterious Beyond to know every weakness of his kind and Ruby who began her search for her family.
In a crater where longnecks saved the world, Littlefoot (Felix Avitia) and his Grandparents (Miriam Flynn and Barry Bostwick) have been around with his Bron (Kiefer Sutherland) and his adopted brother Shorty () along with Sue (Bernadette Peters) her boyfriend and Pat (James Garner) and he and Shorty were about to do the longneck test together.
After the longneck test was over they head for a place where Bron's herd is and help out other led other longnecks to be safe, and over the past years when they were in the valley, Littlefoot (Elijah Wood) and Shorty (Jason Raize) have grown into teenagers and when they were ready to migrate to other places Bron, and Grandma and Grandpa send Littlefoot back to the Great Valley on his own to lead his own herd he misses.
When Littlefoot travel to places he's been to get back to the Great Valley, he stopped at a place where he encountered and Rogue Sharptooth (Gorgosaurus) and was able to escape by jumping into the river where he was drifted away and washed ashore and continues to travel.
In the morning, Littlefoot heard something near him, and he fears it could be the Sharptooth he escaped from, but it turns out to be his old friend, Chomper (James Arnold Taylor) who is also grown as a teenager and traveled together like old times.
When Littlefoot and Chomper entered a forest, Chomper smells something close to them and saw a shadowy dinosaurs running from them and when they followed it they were attack and the shadowy turns out to be an angry Fast Runner (Oviraptor) and when the Fast Runner was about to kill Chomper, Chomper notice the Fast Runner to be Ruby (Grey Delisle) who is grown up and Ruby was surprise to see him and Littlefoot again and told them that her family were looking for her when a Rogue Sharptooth chased them out of the Mysterious Beyond.
While traveling together, they discovered footprints that came from a huge herd of dinosaurs and encountered to Spiketails (Stegosaurus) who turns out to be Spike (Mitchell Whitefield) who is able to talk, and his friend, Tippy (Rickey D'Shon Collins) along with his mother (Susan Krebs) and the herd of Spiketails and their leader (Rob Paulsen) who allowed Littlefoot and the other to join when Chomper told them about the Rogue Sharptooth and travel and Tippy told them that the Great Valley has changed and has enough room for all dinosaurs including his herd who are living there.
Meanwhile the rogue sharptooth that Littlefoot escape from began to track him down and he knows he's not alone.
Later, Littlefoot and his friends along with Tippy's herd stopped and rest to eat while he and the others find something to eat together and then encounters a young flyer (Pteranodon) who happens to be their friend Petrie (Tom Kenny) who was hiding from his new born brothers and sisters and his mother and uncle Pterano were not surprised of him avoiding them and began migrating.
When they stopped to get some water the meet their old swimmer (Saurolophus) friend Ducky (Tara Strong) who has grown into a beautiful teenager and Spike was reunited with his adopted swimmer family and Mrs. Swimmer was surprised to see everyone, including Littlefoot and they all migrate with the other dinosaurs.
As Littlefoot and the others stopped at a field where there are more plants and ground crawlers (bugs) to eat, Chomper, encounted a tempered Three-Horn (Triceratops) and Littlefoot stopped her and then notice that the tempered Three Horn is Cera (Hayden Panettiere) who was playing hide and seek with her little sister Tricia (Meghan Strange) who is grown as her young age with her niece and nephew, Dana and Dinah who were traveling Tria and Cera told them that her father died while saving them and then Ruby was reunited with her long lost family and started moving on cause the rogue sharptooth is far away from them.
At the water where Littlefoot and the others left after seeing Ducky, The Rogue Sharptooth gets a drink and smells senses of the dinosaurs they left.
After moving far away before the sharptooth could catch up, Littlefoot and the others did some new and old games like they did when they were young, and encounters their old friend Guido who is grown up, and their dolphin like creature friend, Mo who is with his family, and they notice that the stampede of dinosaur were running from the rogue sharptooth and caused Littlefoot and the gang to be separated from the herd and ended up in a cave where they meet their old friend Skip who was with Tickles who can speak.
While trying to reach at the end of the cave, the gang encountered Hyp, Mutt, and Nod who used to be bullies but changed and was separated from herd because of the rogue sharptooth and were able to reach the end of the cave and reunited with Hyp's father and Guido, Skip and Tickles joins them while the gang catches up with the herd and Littlefoot promised that he will get his friends back together with their folks.
While trying to find the herd, they encountered Mr. Clubtail (Ankylosaurus) who they haven't seen for years and was eating sweet bubbles (grapes) and gave them some.
As they continued to catch up with their folks, they meet someone they remembered, Mr. Thicknose (Dorian Harewood) who resting so he can continue to move on and catch up with the herd, while they keep trying to get back to their folks.
As the gang reach the top, Chomper spotted the herd that they were separated from with his eye tights and let the others know that they're getting close, but then encountered the Rogue Sharptooth and Chomper and Ruby tries to hold him off while they gang escapes but the gang can't leave them behind and stayed to fight off the rogue and Littlefoot relays that the he and the others will lead the rogue straight to the herd and tries to make sure that he helps his friends get rid of him for good.
During the fight with the sharptooth, Littlefoot pushes down the tree at the rogue to get him closer to the edge of the cliff before knocking him into the pit where he meets his death, and the gang were able to defeat the rogue for the first time when they got older and begins meeting up with the herd.
As the herd got to together with all the dinosaurs from the Great Valley, they noticed that the young ones are alive and was reunited with them thanks to Littlefoot who got them all safe and reunited with Mr. Thicknose , Mr. Clubtails and Hyp, his father and his buddies and Skip, Guido and Tickles even Mo and his family, and everyone was together and sets off to get back to the Great Valley.
The next day, Littlefoot, his friends and all the dinosaurs were able to get back to the Great Valley that has changed for so many years and has enough room for all of them including new comers, and far walkers.
After returning to the Great Valley, Chomper, brought Ruby and her family to the secret caverns, while Tippy's herd lives on a huge field of plants to eat, and Ducky, Spike and their family return their home where Ducky's sibling hatched by the water, and Petrie and his family moved back in to their home and Cera and her half sister and their niece and nephew and their mother Tria return to the nest where Tricia was hatched, and Guido ,Skip and Tickles made themselves at home with Mo's family, and as they gang got together the wonder where Littlefoot could be and, Littlefoot showed them that he'll live on a hill with a long tree surrounded by long grass and showed them the twigs that are one of them that has no leaves means someone died like his mother, and the other that has leaves that means someone's still alive like his father, Bron, his grandparents and his brother, Shorty, and began their new lifes together and will begin their new adventures in the Great Valley, the Mysterious Beyond and other places someday as they're all grown up together.