It's wrong to copy things.
Lewis is comes from a family of talented artists, and he is entering the school art competition.
Lewis wants to win the competition.
Lewis puts a lot of effort into his painting asks his older sister for advice on how to make his painting look better.
Lewis finds one of his older sister's old paintings that he thinks is really good and copies it for his submission.
Lewis improves his art skill and enters his best work into the competition.
Lewis's family discover that he copied his sister's painting and alert the school to have him disqualified.