Invisible Ink

 Trip of school students - a curious student - having fun with classmates- in a fort- which had a story of hidden treasure - found a blank paper - some classmates also saw that- the curious student knows about the story of hidden map- not ready to hand over the paper - got in a fight - was in a bad shape - but didn't gave up - did many experiments with blank paper - found the results of the experiments - went to check the way - one demon/ creature were there - again had a fight - had some questions, answers round - got the reason for the treasury to be hidden- got that and did charity with that.