Lou

Lou is a dragon who loves gems. In cold evenings, they go to the caves of Mount Everest and searches for diamonds and gems. They're unlucky if they find about 24, because there are a lot in the specific caves they search. But a problem appears: The caves are mysteriously running out of gems and diamonds to provide. It's not because of Lou, because they always put the gems back once they look at them for about a day or two. They get you to help them find out what is doing this, and stop it.