The Land Before Time XV: Legend of the Golden Longneck is a direct-to-video animated musical adventure feature and the fifteenth film in The Land Before Time series.
It stars Debi Derryberry, Anndi McAfee, Grey DeLisle, Jeff Bennett, Rob Paulsen, Candi Milo, Meghan Strange, Kiefer Sutherland, Frank Welker, Albert Brooks, Chris Rock, Thomas F. Wilson and Reba McEntire.
It is the first time James Horner's original themes (including instrumental uses of If We Hold on Together) from the first film are heard in a Land Before Time film since Journey to Big Water.
Bron opens up a Great Valley playground, and Littlefoot is heavily anticipating being rewarded best kid of the new playground. But to his dismay, Guido gets the reward instead because Littlefoot is supposedly not mature enough for the reward. Meanwhile, Smek finally stops fooling around and enacts his greatest plan to steal the secret Treestar formula, he steals Parsley's Golden Longneck, sends it to the dangerous Museum, and frames Bron for it. When Parsley finds his Golden Longneck missing, he crashes the Great Valley playground and charges Bron for the theft, but Littlefoot is willing to travel to the Museum to retrieve the Golden Longneck, so Parsley gives him, Cera, Ducky, Petrie, Spike, Chomper and Ruby six days to find it, during which he has Bron frozen.
While Littlefoot, Cera, Ducky, Petrie, Spike, Chomper and Ruby head off on their adventure, Smek makes it past the frozen Bron and successfully steals the Treestar formula. He then gives away helmets with all the Treestars he sells, which then turn his customers into his monument-building slaves. Can Littlefoot, Cera, Ducky, Petrie, Spike, Chomper and Ruby successfully retrieve Parsley's Golden Longneck and save the Great Valley...?
Littlefoot wakes up from a dream where he has been appointed the best kid of the Great Valley, excited that he believes today to be the day it will come true. Because today is the Grand Opening Ceremony of the Great Valley playground! He goes through his early morning cleanliness routine, and heads out the door to the ceremony, but not before checking by at Guido's first. Meanwhile, Smek is ranting about how unfair it is that Bron is opening a new restaurant and he, Smek, has never even had one victim. That is until, Emily informs him about unused Plan Z, which is his most diabolical plan yet, and he sets off to put it into action. Meanwhile, Bron unveils the new manager of the Great Valley playground— Guido. This doesn't stop Littlefoot from making a scene though, not out of rage, but out of confusion. He walks home in a depression.
That night, Smek walks to the Dino-castle of Parsley, where Parsley's son, Juno, is trying to persuade him to try some love and compassion instead of cruel and harsh punishments. After lecturing his son on the importance of ruling the sea, Parsley realizes that his Golden Longneck has been stolen, and goes into a frenzy while Smek flies away from the castle with the Golden Longneck in his claws. Littlefoot is trying to pull himself together, and almost accomplishes it until the untimely arrival of his friends, Cera, Ducky, Petrie, Spike, Chomper and Ruby. Littlefoot informs his friends of what he missed, and starts to go home before he hears Cera order a Triple Chocolate covered Ice Cream. Desperate for a measure to cheer himself up, Littlefoot stays for one. Then another. Then ten more. Needless to say, he and his friends end up getting drunk and passing out over ice cream.
Littlefoot awakes in the morning loopy and droopy from last night having a G-Rated Hangover. He realizes he's late for the ceremony and speeds off to the Great Valley playground, full of spite and hatred towards his father. But he's not the only one heading there. Parsley is walking over, and Bron exposes himself at once, thinking Parsley's there for spending. Unfortunately, he's not, and immediately calls him out for a note Smek left there, stating that Bron stole the Golden Longneck. Out of fear, Bron explains that anyone would vouch for him, only for Littlefoot, still in hangover mode, to stumble through the door. Unaware of the consequences of his actions, Littlefoot calls Bron a big jerk in front of Parsley. This is enough for Parsley to finally attack Bron, restoring Littlefoot to his rightful senses, and telling him that he won't let him burn Bron. Parsley is ready to fry them both, but Juno steps in and asks his dad to give Littlefoot a chance to reclaim the Golden Longneck, which is now in the forbidden Museum. Littlefoot accepts this chance to save his dad, and with Cera, Ducky, Petrie, Spike, Chomper and Ruby at his side, the seven speed off in the Dino-Mobile, an vehicle that Bron built for his son, on the road to the Museum.
Parsley leaves with Bron frozen wear he stood, so that he won't go anywhere. While Bron is like this, Smek finds it pretty easy to slip by him and take the secret Treestar formula. He takes it back to the Dino-Mansion, and begins with rapid marketing. Eventually, Littlefoot, Cera, Ducky, Petrie, Spike, Chomper and Ruby come to the county line, where their mobile is stolen, but their spirits are high for he rest of the day. After Emily points out to Smek that the seven Dino buddies could stop his plan from working, he informs her that he hired a homicidal predator to hunt them down and do what he must do. Fortunately for them, he hasn't crossed their path yet, but they are getting rather tired without their mobile. That is until they come across a biker club with the mobile parked just outside. In an elaborate and highly not well thought out plan, sheer luck reunites Littlefoot and the key, and the seven can continue their journey on wheels.
Back in the Great Valley, Smek has out done himself, and everybody in this valley has come to the Dino-Mansion to buy Treestars with free helmets with purchase. Of course, this plan is more than just becoming a successful business man. When everyone in this valley has a helmet on, Smek is able to start phase two of his plan, and with the single click of a button, the helmets take over the minds of every one wearing them, and force them to do his bidding. This is all, of course, unbeknownst to Littlefoot, Cera, Ducky, Petrie, Spike, Chomper and Ruby, who come across an ice cream stand, which they immediately flock to. Unfortunately, this is no ordinary stand; it's actually a giant Tyrannosaurus Rex (that was defeated in the ending of the first movie) that lures in its prey using the stand as a cover up. Littlefoot and his friends narrowly escape, but lose the mobile again, this time for good, and now they must face a larger obstacle, a deep, dark, dangerous, hazardous, monster infested trench.
Before they go down, however, Juno stops them and offers some encouragement. This, however, quickly goes south, as the seven break down at the information of Smek's take over. There's no other way, she has to trick them with her "dinosaur magic". She has them close their eyes, and she puts some leafs under their noses to fool them into thinking that their men. With their sudden bursts of maturity, the seven jump down into the trench, convinced that they're now invincible. But as far as things go in the trench, they're pretty much correct. They make it through (in song) while various hazards come within mere inches to keeping them as a meal, but they hardly even notice. In fact, they eventually have a slap dance contest, which ends up winning the monsters friendship, and they let them through he trench unharmed.
Once out of the trench, the Museum is as good as theirs. That is, until they're stopped by Dennis, the assassin Smek sent to get rid of them. But before he can step on them with his foot, he himself is stepped on by a giant, skeleton boot. At first Littlefoot sees it as a unknown friend who saved their lives, but is quickly taken aback when it reveals itself as the Dinosaur Hunter that guards the Museum, and the seven are taken captive. When they awake, they are trapped inside a wall of grids (a cage). It is then revealed that the Dinosaur Hunter owns a gift shop where he sells sundries. The seven see him make a humorous diorama of "Mr. Elephant Jumbo" right before he takes them out and places them under a heat lamp for drying. The seven have a sad moment where they think they failed in ever reaching the Museum, but Cera reads the sign of the gift shop which is actually the Museum. The seven have a last look around to find the Golden Longneck, which is standing on a table next to them, and sing one last chorus of the Best Friends song before shedding a tear apiece, and completely drying up, becoming no more than live action skeletons of Apatosaurus, Triceratops, Parasaurolophus, Pteranodon, Stegosaurus, Tyrannosaurus Rex and a Oviraptor.
Their tears slide down the table that their (presumably) dead bodies are laying and meet in-between them, forming a heart, before sliding down all the way off and down an electrical chord and into an outlet, causing the fire sprinklers to go off, instantly restoring them to their full and healthy state. They escape the Dinosaur Hunter, get the Golden Longneck, and run out of the Museum and onto the fields. Their means of getting back to the Great Valley, however, are looking pretty grim, and it is at that very moment that Parsley is on his way over to the Great Valley playground to perform the execution of Bron. But with one last hope, Etta comes flying towards them on the fields, volunteering to take them there. They ride on Etta's back to the Great Valley, but not before shaking of Dennis (who survived being stepped on) one last time. Once they get to the valley, Littlefoot fears that they won't be able to fall down in time, which is when Etta uses a catapult to shoot them straight down to the valley reflecting the fiery beam coming out of Parsley's trident just before it makes contact with Bron.
With the Golden Longneck back, you'd think that everything would be fine, right? Wrong. Smek releases the umbrella to keep the rain off of his parade, which happens to be a giant helmet right on top of Parsley's head. Smek orders all his helmet zombies after the eight people still not in his control (aside from the still frozen Bron), and they're cornered in the Great Valley playground. Smek monologues for a bit, but before he can order the final attack on the eight, Littlefoot breaks out in an ultimate rock song, which is powerful enough to shoot beams out of the end of his guitar and free the people from Smek's helmets. In an attempt to escape, Smek is stampeded and eventually sent to jail. Parsley returns Bron to normal, the citizens are free from Smek's evil helmets, and Littlefoot is finally appointed best kid of the Great Valley playground.
- Debi Derryberry as Littlefoot
- Anndi McAfee as Cera
- Grey DeLisle as Ducky
- Jeff Bennett as Petrie
- Rob Paulsen as Spike, Guido, Mo and Mr. Clubtail
- Candi Milo as Chomper
- Meghan Strange as Ruby
- Kiefer Sutherland as Bron
- Frank Welker as Smek
- Albert Brooks as Parsley
- Chris Rock as Juno
- Thomas F. Wilson as Dennis
- Reba McEntire as Etta
- Nika Futterman as Emily and Tricia
- Tara Strong as Ali
- Tress MacNeille as Mama Flyer and Mama Swimmer
- George Bell as Topsy
- Barry Bostwick as Grandpa Longneck
- Miriam Flynn as Grandma Longneck
- Dorian Harewood as Mr. Thicknose
- Camryn Manheim as Tria
- Cree Summer as Tippy
- Elizabeth Daily as Shorty and Rhett
- Patrick Warburton as Big Daddy
- Matthew Lillard and Seth Green as the Dinosaur Hillbillies
- John DiMaggio as the Thug Bar leader
- Mindy Sterling as Old Lady
- Stephen Stanton as the Dinosaur Hunter (live-action)
- This is the first "The Land Before Time" film to include live-action scenes.
- While Big Daddy appears in this movie, his kids are absent.
- Some of the cast are different due to avoid recasting.
- Some of the original cast beside the Gang of Seven returns in this movie.
- The film's script and plot are a spoof of The SpongeBob SquarePants Movie.
- Littlefoot has all of SpongeBob's places, moves and lines.
- Cera, Ducky, Petrie, Spike Chomper and Ruby have all of Patrick's places, moves and lines.
- Bron has all of Mr. Krabs' places, moves and lines.
- Smek has all of Plankton's places, moves and lines.
- Guido has all of Squidward's places, moves and lines.
- Parsley has all of King Neptune's places, moves and lines.
- Juno has all of Mindy's places, moves and lines.
- Dennis has all of Dennis' places, moves and lines.
- Etta has all of David Hasselhoff's places, moves and lines.
- Emily has all of Karen's places, moves and lines.
- Ali has all of Sandy's places, moves and lines.
- Mama Flyer has all of Mrs. Puff's places, moves and lines.
- Mr. Thicknose has all of Perch Perkins' places, moves and lines.
- the Dinosaur Hillbillies have all of Floyd and Lloyd's places, moves and lines.
- the Thug Bar leader has all of Victor's places, moves and lines.
- Old Lady has all of the Ice Cream Lady's places, moves and lines.
- the Dinosaur Hunter has all of the Cyclops' places, moves and lines.