In order to save his mother, a young man embarks in an adventure to get proof of a friendly monster’s existence.

To save his sick Mother, a Young Boy? must get proof of the?existence of a ?being not known to science, so he travels far and wide and brings back a friendly Monster to everyone's surprise.

Not great but you get the idea to simplify it.?? I hope.

Well, then, maybe ?something like:

To pay for an operation that will save his sick mother's life, a poor boy enters a contest to prove the existence of a legendary magical monster. ?(27 words)

I don't understand. ?What is the cause-and-effect link between proving a monster exists and saving his mother. ?What is the inciting incident, the threat, ?that compels him to find this monster in order to save his mother? Check out the "Formula" at the top of the web page for guidelines on writing an industry standard logline.