u/Kindly-Flight-6909

I've spent far too much time thinking about what the plot Mamma Mia! 3 could be, so I thought I'd share one idea here just for fun and see what everyone thinks. Tried to organise it so makes sense.

• Sophie's arc: She gradually realises she needs to discover who she is outside of Donna's legacy. Donna spent her whole life giving Sophie opportunities she never had, so it feels right that Sophie's arc reflects that.
• Sophie and Donna: As Sophie begins questioning what she wants from the next chapter of her life, she starts asking Tanya, Rosie and the three dads to tell her stories about Donna that she's never heard before. She starts writing them down to preserve the memories, hoping they'll help her understand what the next chapter of her own life should look like.
• The Flashbacks: Each conversation unfolds into flashbacks. Lily James returns as young Donna. Show her bringing sophie up. Also answers questions like 'why did she never leave the island?'. Parallels Sophie's journey in the present, raising her child.
• Bill and Rosie as an established couple: They're happy, settled, and affectionate, but their relationship isn't a major plotline.
• Tanya's Arc: Tanya rejects another marriage proposal and finds complete fulfillment as a wealthy, independent single woman. Could focus on her investing her vast wealth into a passion project. Shows a woman's happy ending doesn't require a romantic partner.
• Hand the resort over to Sam, Bill and Harry. It gives the original cast a permanent reason to stay on Kalokairi while freeing Sophie to discover who she is outside of Donna's shadow. It also opens the door to endless comedy - Sam desperately trying to run a professional hotel while Bill and Harry unintentionally sabotage him
• Meryl Streep's Role: Streep appears strictly in late-stage flashbacks, dream sequences, and final musical numbers, keeping the consequences of her character's death intact.
• Sophie's calling: Sophie realises as she writes down the stories she hears how much she loves hearing about and writing them (goes back to how her story began reading Donna's diary). She realises that writing stories is what she wants to do.
• A decision and an equal parnership : Remembering how the first film ended, Sky and Sophie make a joint decision to continue the adventure they began years ago, seeing more of the world while Sophie writes and they raise their child. They decide to leave the island (with the explicit promise they will always come back to visit) so they can both pursue their dreams and create new experiences.
• The Ultimate Departure: The emotional climax features Amanda Seyfried singing ABBA’s "I Wonder" (like young Donna in the second film) as she, Sky, and the baby board a boat to start their new life. The three dads, Tanya, and Rosie see them off. Like Donna, Sophie leaves the place she knows to discover what's next. Unlike Donna, she leaves with the love and support of the family Donna built, knowing she'll always have somewhere to come home to.

A package arrives back on Kalokairi months later. Sam, Bill, Harry, Tanya and Rosie gather around a table and open it.

Inside it is a newly published book:

Thank You for the Music: The Story of Donna Sheridan
by Sophie Sheridan

Then they open to the dedication...

• fade to singing with the whole cast

I would also love if after Mamma Mia 3 they release a prequel for example titled The Dynamos. Could be a coming of age story about how the dynamos formed and how their personalities developed into the women we know.