Unfortunately, I couldn't find a publicly available PDF script of "Descendants" that you can download. However, you can try searching online marketplaces or script databases that sell or provide access to movie scripts.
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Disney's Descendants: The Musical is a brand-new stage version featuring hit songs from all three films, including "Rotten to the Core," "Evil Like Me," and "If Only". The script is structured as follows: Descendants the Musical - Manhattan Arts Center