After seeing so much damage, Brian states that the trouble maker was an Apatosaurus. And everyone decided to capture it. But they didn't invite Snowdrop because they think she'll get killed or hurt (due to her blindness). So Snowdrop decides to find one herself then she meets the Apatosaurus named "Arlo". And they started to make good friends.
It was a beautiful morning in Equestria, Berk, and Quahog. But then there is a rumble, and then a roaring that disturbs the dragons. Afterwards, they come outside and see wreckage. Brian then concludes that is was a dinosaur that caused the wreckage, and Snowdrop wondered who it done it. Later, Brian sings a song how a dinosaur can wreak havoc in cities. And after the song they decide to go "Dinosaur Expedition" to capture it. However, they don't let Snowdrop join them, because they were afraid she'll get hurt due to her blindness and Yuna and Hiccup had to agree. So, Snowdrop decides to head back to Canterlot Castle.
Later, Snowdrop is lying in her bed. Till the Human Mane 5 come in, and then Snowdrop starts crying. And Human Fluttershy asks what's wrong, Snowdrop explains that she wants to catch a dinosaur and Human Fluttershy pets her back. And, Human Rarity then decides to tell her to stand up for herself. But Snowdrop rejects the idea and decides to head to the cemetery. Once Frostlord flies into the cemetery, Eaglesight guides Snowdrop to Primrose's tombstone. Snowdrop says hello to her, and then explains about her desires to catch a dinosaur and how the others don't want her to come due to her blindness. Despite having 2 dragons, she then begins to cry again. Then she hears a voice. And it was Primrose in spirit form, she then tells Snowdrop to let her heart follow her dreams. And she will always be by her side, and fades away. Snowdrop tearfully farewells her mother when the Human Mane 5 come to take her home. After they arrive back home, she falls asleep.
The next day/Dinosaur forest
The next day, Brian and the others have gathered up their supplies and they set off for the forbidden Dinosaur forest. As they journey off for the forest, they reach it's outside electric fence. And Celestia states it was once a park, it was closed down during a incident. They then reach some footprints, but start to hear noises. After looking around they see a Stegosaurus charging at them and starts swinging it's tail. They duck and jump as they avoid the spikes on it's tail. And it knocks Yuna down and stand up tall but Brian shoots and kills it with a Thompson. The team then go on, while Snowdrop, Eaglesight, and Frostlord sneak into the gate. They begin to search the place for any kind of dinosaur.
Snowdrop meets Arlo
As Snowdrop searches, she begins to hear noises of nearby Dinosaurs. Frostlord keeps a sharp eye out for any dinosaur that could try to attack, then they see a old building. So they take a closer look at it inside they hear breathing and a head pokes out. Snowdrop is at first startled but she calms down and it whispers in her ear. Nervous she crawls out revealing an Apatosaurus! The Apatosaurus then reveals his name "Arlo". Snowdrop then introduces herself, and then her dragons. But decides to head back to find the others. She and her dragons then head for the gate, but Arlo thinks they're having fun. So she follows him around. Meanwhile, out in a field the team are still searching. And some Dinosaurs are eating grass when a T-Rex appears! The T-Rex then chases a few dinosaurs before killing a Triceratops. The team then decided to hunt in the forest instead. So they race for the forest.
Back to Snowdrop and Arlo
Returning to Snowdrop, Arlo thinks they're still playing. And keeps following them, till finally Snowdrop says, "We aren't playing!". Arlo then stops and wonders why. Snowdrop explains that she's captured him. And is starting to get annoyed with Arlo by him saying "Why?". And then she tells him to be quiet. But he does and cries a little, but Snowdrop tells him sorry. Then they hear a roar. After looking around, they find it was Arlo's father calling for him. But Snowdrop states he can't see him yet. And then explains that she is blind, so she needs Eaglesight to help guide her around.
Back to team/Having fun
Back with the team, they are waiting for an ambush. After a while, they hear something (believing it was the Apatosaurus). And it yanks up to a rope trap, but it turns out to be Zoe! She was cross at them, and then Peter shoots her down. (by shooting the rope). Zoe then explains that if they do that again, they'll feel pain that's never invented. Brian then states they'll never do it. Back with Snowdrop, the dragons, and Arlo; they cross the gate, and then Snowdrop then calls out for everyone, but no one answer. After looking around, they find that no one is around. So then, Arlo decides to have fun. Snowdrop is at first, not so sure, but she hears him laughing. So, she joins him after playing, they were dirty. So they jump into a pond, and faster that they roll down a hill and laughed.
Heading back to Canterlot
Later, our heroes start to head back for Canterlot and see the wreckage and start to panic. Then, after Fishlegs said "traps". That gave Brian an idea. They then get some supplies and then make traps. Later, Snowdrop, her dragons, and Arlo hear his father again. So they decided to find him, but unknown to them the T-Rex is following them. Later, the Human Mane 5 are out looking for Snowdrop, when Human Rainbow finds the sign to Dinosaur Park. And Human Fluttershy wonders if that's where she is. So they go to find her but then Primrose (in Spirit Form) appears and decides to help them.
Arlo loses hope
Meanwhile, Snowdrop, her dragons, and Arlo continue searching for his father, but he starts to give up. But Snowdrop tells him not to. And then he cheers up. But then, our heroes see them. Brian then assumes that Arlo has come to capture Snowdrop so they charge, he runs but some of our heroes fall into their own traps. Snowdrop finds Arlo inside a cage trap. And tells her that won't be scary. Eaglesight then helps snowdrop get to the rope and she frees Arlo. The Human Mane 5 and Primrose watch her actions and are amazed. As Primrose tears up, then the others arrived. They see Arlo and then charge again and begin to rope and chain him, but then Frostlord stops them from continuing as Snowdrop explains that Arlo is not dangerous. Brian is about to protest and willing to shoot Arlo, he's about to draw his pistol, when the Human Mane 5 and Primrose interfere. Princess Luna is surprised to see Primrose. And Human Fluttershy asks what's going on. Brian is about to speak when Snowdrop explains that she is friends with Arlo. And states that he's not dangerous, realizing she's right. (Blythe even recalls that she befriended Rexy, Blue, Delta, Echo, and Charlie) They let him go.
The T-Rex returns/Arlo's father comes
Then there was a loud roar, then out form the woods appears the T-Rex! Terrified, Arlo makes Snowdrop go flying and land in a log dam blocking a river. Everyone races for the log dam, she falls down further as everyone tires to hold off the T-Rex. Arlo then realizes they need more help, so he makes his first roar and then his father comes in! Knocking the T-Rex down to the creek. And then Arlo explains the situation, so his father then reaches his neck down. But the T-Rex starts climbing up. Arlo's father manages to reach Snowdrop and then he gets her to safety just as the T-Rex reaches the top, the logs crack and the stream gives way drowning the dinosaur. Arlo and his father helped Snowdrop down and she and Primrose hugged her. Brian then apologizes to Arlo for almost killing him. He accepts his apology. And Primrose begins to fade away, Snowdrop begs her not to go. But Primrose explains that she will still be with her no matter what, but she will visit time to time and then she fades away. Snowdrop weeps for Primrose again, but calms down when Frostlord, Eaglesight, and Luna comfort her. And Yuna then states that she, Luna, and Hiro are her family now, will always be her little sister. As Nightstar agrees. Arlo and his father decide to ask Snowdrop to play with him. Snowdrop agrees and then decides to play with him. Yuna then plays a message, as it shows 2 clouds pairing the duo. As the movie ends with "Together We Made a Promise" playing.
- Barney the Dinosaur, BJ, Baby Bop, and Riff guest star in this film.
- This film is based off of "Pooh's Heffalump Movie".
- Rexy, Blue, Delta, Echo, and Charlie are mentioned in this film
- This film marks it's first appearance of Arlo in the franchise.
- Primrose (in spirit form) guest stars in this film.
- Beautiful morning/Wreckage
- That night/Primrose
- The next day/Dinosaur forest
- Snowdrop meets Arlo
- Back to Snowdrop and Arlo
- Back to team/Having fun
- Heading back to Canterlot
- Arlo loses hope
- The T-Rex returns/Arlo's father comes
- Heffalumps and Woozles - Brian
- Interstellar theme - (when Primrose's spirit form appears)
- Dinosaur - The Attack [when Brian, Peter, and the dinosaur herd are being chased by the T-Rex]