Littlefoot's Adventures of The Little Mermaid: Ariel's Beginning is the first Land Before Time/Little Mermaid crossover film planned to be made by Daniel Esposito. It will appear on Google Drive in the near future.
King Triton and his wife, Queen Athena, rule over the underwater kingdom of Atlantica, which is filled with music and laughter. They have seven young daughters, the youngest of whom is Ariel. The merfolk are shown relaxing in a lagoon above water, and Triton gives Athena a music box. Suddenly, a pirate ship approaches. Everyone escapes except Athena, who is crushed by the ship when she tries to save the music box. Devastated by Athena's death, Triton throws the music box into the ocean and bans music from the kingdom.
Ten years later, Ariel and her six older sisters live under a strict routine maintained by their governess, Marina Del Rey and her assistant, Benjamin. Marina hates being the girls' governess and longs to be Triton's attache, a job currently filled by Sebastian the crab. Ariel is frustrated by their current lifestyle, which brings her into conflict with her father. One day, Ariel encounters Flounder, a young fish whom she later follows to an underground music club. She is overjoyed by the presence of music, and is shocked when she sees Sebastian performing there. When her presence is revealed, the entire band stops playing and hides, believing Ariel will tell her father about them. Ariel sings a song explaining her love of music and the remembrance of her mother and she joins the club with an oath.
Ariel returns to the palace, and her sisters confront her over her disappearance. She explains where she was, and the following night all seven sisters go to the club to have fun. Marina secretly finds them, and she later reports their activities to Triton. Sebastian, Flounder and the band are sent to jail, while Marina gets the job she wants.
Triton confines his daughters to the palace, which results in Ariel asking him why music isn't allowed. Triton refuses to answer and shouts that he won't have music in his kingdom. Distraught, Ariel says that Athena wouldn't have wanted music to be forbidden and angrily swims to the girls' bedroom, her saddened sisters soon following. That night, she decides to leave Atlantica and frees the jailbirds. Sebastian leads them to a deserted place far from the palace where Ariel finds Athena's music box, as Sebastian hoped. Ariel and Sebastian decide to return to Atlantica to bring the music box to Triton, hoping that it will change his mind, as he has forgotten how to be happy after Athena's death.
On the way back, they are confronted by Marina and her electric eels. Marina wants to stop them so she will retain her position of "power", and a struggle ensues. It ends when Marina barrels towards Sebastian, but Ariel pushes her away, getting hit in the process. Triton arrives in time to witness this, and he is remorseful for his actions. He sings the lyrics of "Athena's Song", and Ariel wakes up. The film ends with Triton restoring music to Atlantica and appointing Sebastian as the new court composer, much to everyone's glee. Everyone rejoices except Marina, who has been sent to prison.
- The Vultures (Buzzie, Flaps, Dizzy, and Ziggy), Jiminy Cricket, Zazu, Mo, Ali, Bron, Shorty, Mr. Thicknose, Pterano, King Julien, Maurice, Mort, Terk, Tantor, Genie, King Louie, Celebi, Scooby-Doo, Shaggy Rogers, Fred Jones, Daphne Blake, Velma Dinkley, Scrappy-Doo, Woody Woodpecker, Ttark, Bugs Bunny, Daffy Duck, Ozzy and Strut, Rinkus and Sierra, Wile E. Coyote, Pete, and Team Rocket (Cassidy and Butch) guest star in this film.
- This film marks the first debut of Grandpa Longneck and Grandma Longneck.
- Ozzy, Strut, Rinkus, Sierra, Pete, and Team Rocket (Cassidy and Butch) will work for Marina Del Ray in this film.
- This is an NTSC film with NTSC bits from The Land Before Time films, The Jungle Book 1 and 2, Pinocchio, The Lion King films, the Madagascar films, the Tarzan films, the Aladdin films, Pokémon 4Ever, the Scooby-Doo films, and the Looney Tunes films.
- The storyline continues in Littlefoot's Adventures of The Little Mermaid (TV series), Littlefoot's Adventures of The Little Mermaid, and Littlefoot's Adventures of The Little Mermaid II: Return to the Sea.
- King Julien, Maurice, Mort, Terk, Tantor, and Genie originally met Ariel, Flounder, and Sebastian in Simba, Timon, and Pumbaa's Adventures of The Little Mermaid, but those characters were removed from the upcoming remake version of that film because Yakko Warner will remake it as a prequel to Pooh's Adventures of 101 Dalmatians: The Series, so they ended up guest starring (and meeting Ariel, Flounder, and Sebastian) in this film instead because Yru17 believed that they should still be in a crossover film with The Little Mermaid.
- Yru17 originally planned to re-edit this film, but he retired from re-editing anymore crossovers, so Daniel Esposito (who will make Ash's Adventures of The Little Mermaid: Ariel's Beginning) will make this film instead.
- Buzzie the Vulture, Tantor, King Triton, and Shelbow are voiced by Jim Cummings.
- The Jungle Book, Pinocchio, The Lion King, Tarzan, Aladdin, and The Little Mermaid: Ariel's Beginning were all made by Disney.