When a spell is set upon the land a young warrior must fight for her independence.

To Piggyback off what Cajsa said:
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When (An evil wizard) casts a spell upon the land (Entrapping the people) a (young) warrior must discover how to destroy the evil magic if she's to (Free her people)
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1: Is there a better adjective you can use instead of 'young' to describe the protagonist?
2: Is the warrior fighting for her independence or to free the land?
3: As Cajsa asked, what does the spell do, I wrote, entrapping the people, but that was just a guess.
4: Same as number 3, I had to guess that it was an evil wizard who cast the spell, not sure if I got that right.

Hope this helped

You have all the components which is great! But the logline is a bit vauge and would benefit from some clarity. What kind of spell is it? Who cast it and why? Why must the young warrior fight for her independence? Who is the young warrior and how will she fight?