Weekenders Adventures of Barbie in A Mermaid Tale is the first upcoming Weekenders/Barbie crossover film to be created by Sonic876. It will appear on Google Drive or Dropbox in the near future.
Merliah Summers is an avid surfer in Malibu. While participating in a surfing competition, Merliah loses concentration when her hair spontaneously streaks pink, and wipes out. While underwater, she discovers that she can breathe in water, and is approached by pink-purple dolphin named Zuma, who wants to talk to her.
Merliah tells Break, her grandfather, of the incident. Break explains that Merliah's mother is a mermaid, and that Merliah was given to Break as a baby to raise because she was born with legs. Merliah doesn't believe him and goes to her friends Fallon and Hadley, telling them the story.
Zuma appears to the girls, confirming that Merliah is half-mermaid. Zuma explains to Merliah that her mother is Calissa, previous queen of the underwater kingdom of Oceana. Oceana's current queen is Eris, Calissa's sister, who is a tyrant and took the throne when Calissa went missing years earlier. Zuma hopes that Merliah will claim her birthright and usurp Eris. Merliah refuses, and in her anger throws the necklace she'd been wearing since she was an infant. The smashed pendant reveals a magical image of Calissa, confirming that she is alive. Merliah agrees to go to Oceana in the hopes that Calissa can make Merliah normal again.
With Zuma as her guide, Merliah arrives in Oceana and meets Zuma's mermaid friends, Kayla and Xylie. Kayla and Xylie give Merliah an outfit to hide her legs, and together they visit the Destinies, three mermaids with prophetic powers. The Destinies tell Merliah that she needs to collect three items in order to succeed in overthrowing Eris: the Celestial Comb, a Dreamfish and Eris' protective necklace. The group search for the items, occasionally calling Fallon and Hadley for help with research. They find the Celestial Comb in an underwater cave and the Dreamfish in the Adenato currents.
In order to obtain Eris' necklace, Merliah, Kayla and Xylie approach Eris, performing a song and dance to distract her long enough for Merliah to grab Eris' necklace, but soon has her mermaid tail pulled off, revealing her legs. In a rage, Eris creates a whirlpool to banish Merliah to the deepest depths of the ocean. While inside the whirlpool, Merliah calls the Dreamfish for help. The Dreamfish offers to grant Merliah's deepest wish and send her back to Malibu and erase her mermaid half for good. Merliah rejects the wish and accepts her responsibility as princess of Oceana. Due to this, Merliah is given a real mermaid tail, which she uses to escape the whirlpool herself. Merliah reveals her identity to the people of Oceana, proving her identity by brandishing the Celestial Comb. Eris rushes Merliah, and after a chase Merliah is able to lure Eris into the whirlpool. Eris is trapped and sent into the deepest depths of the ocean.
Merliah finds and sets Calissa free. Calissa is queen again, and makes Oceana healthy once more. In the aftermath, Merliah confesses that she misses her life as a human, and Calissa gives her a magical necklace that enables her to be a human or mermaid whenever she wishes. Merliah then returns to land, where she is reunited with her grandfather and wins the surfing competition.
- Littlefoot, Cera, Ducky, Petrie, Spike, Chomper, Ruby, Guido, Grandpa Longneck, Grandma Longneck, Lincoln and his sisters, Twilight Sparke (Human Version), The Human Mane 5, The Mighty Morphin Power Rangers, Scooby-Doo, Shaggy Rogers, Fred Jones, Daphne Blake, Velma Dinkley, Timmy Turner, Cosmo, Wanda, Poof, Sunset Shimmer (Oposite), Lord Zedd, Rita Repulsa, Goldar, Foop, Vicky, Denzel Crocker, and Megan are guest starring in this film.
- Sunset Shimmer (Oposite), Lord Zedd, Rita Repulsa, Goldar, Foop, Vicky, Mr. Crocker, and Megan will be working with Eris, even thought good Sunset Shimmer appear in Pooh's Adventures of Barbie in A Mermaid Tale.
- Sci-Twi and Spike the Dog will be absent due to their past adventure.
- The storylines continues in Weekenders Adventures of Barbie in A Mermaid Tale 2.