Disney Descendants has had a lot of good ratings over the time its been premiered on Disney channel and every fan once to know what was that look Mal gave at the end so my thoughts were they need to make a 2nd one and i have a great idea for it but it may take a while to read so get comfortable because here i go!
First of all we would start out with "Mal: remember the last time we talked well i do and it ended with the coronation night well what you didn't know was that something happened after that night which brings us to our new story 3 months later" and then we would jump right into the story. the whole movie is based on what happens after the first movie and of course it needs to be interesting so why not throw maleficent into the mix right off the bat she is back to full form and escapes and goes into hiding while the kingdom is searching for her and terrified what would happen if she came back she is working on her plan which is to make a clone of Mal to capture real Mal and bring her back to maleficent to imprison her while her clone takes her place and goes undercover to destroy Auradon and have maleficent take over the world and get her revenge. Of course maleficent didn't make an exact clone so Ben, Evie, Jay, and Carlos notice somethings off with her but decide not to worry about it... yet.
Later clone Mal starts doing evil things which leads Ben to think that it isn't really her and decides to look farther into the occurrences. at the same time real Mal escapes maleficent and heads to Auradon but she know it will be a long and dangerous journey especially with maleficent out looking for her. Meanwhile Ben figures out that the Mal that is with him isn't the real one and captures her and tries to get her to talk. while Mal is heading back to Auradon she faces some problems along the way that maleficent had put down for her. She has to beat in order to go ahead on her journey she ends up getting scraped up and a sprained ankle but keeps going because she knows she is almost there. at Auradon Prep Ben decides to go into the "or else" mode which the clone tells him if he hurts her then he hurts the real Mal too which Ben of course doesn't dare lay a hand on her but still is angry and worried about Mal.
Mal eventually gets to Auradon and she finds Ben and her clone Mal knows that she has to battle her clone and defeat her but if she does then she may also end up dying too but she does whats right for Auradon and ends up dying but since Ben and all of her friends love her and care about her the curse doesn't work and comes back to life. they of course are happy and hug her but then maleficent bursts in and Mal says that its our fight leave them out of this maleficent says okay and traps Evie, Ben, Carlos, Jay, Audrey, Jane, and Doug in a magic unbreakable cage Ben tries to get out but he can't. The fight begins and Mal gets knocked down thrown across the room and into the wall from maleficent's magic. Mal slowly gets up limps towards her mother and throws her to the ground with a spell lifts her up into the air and throws her onto the floor maleficent gets up Mal throws some sort of purple fireballs at maleficent and she/maleficent gets knocked back a little with each one finally maleficent casts a spell and they both cast a spell at the same time and they end up colliding and at first maleficent is winning but then Mal uses all her strength her nose bleeding in concentration and power and blows maleficent to the ground taking her/maleficent's powers she falls to the ground the magic cage dissolves and everyone runs to her Ben lifts up her head and she says did i win Ben laughs and says yes he gives her a hug and they both start crying.
Later, Mal is recovering still but is able to walk using crutches and they end with the last song of the 2nd movie.