(This would actually be kind of a cool plot for a mystery novel? Asshole rich old fart thinks their grandkids are worthless and just want their money, so makes a big fuss about this valuable, easy-to-steal collection they have as a test, only the collection is actually worthless - they wouldn't risk their real money - and also someone gets murdered. Who knew the collection was actually worthless? Who would be willing to kill for it? Who knew Grandma had actually made a mistake, and there's one item in the lot that really is priceless?)