you collect antiques and regularly travel the country looking for good deals. in your wanderings, you find an old fiddle and offer the owner $5. the owner accepts, and you take your treasure home. after you get the fiddle home and do your research on it, you discover the fiddle is actually worth $5,000. what a find! what do you think would happen if the owner tried to cancel the contract and get the fiddle back? mistake of value is not a valid defense to a contract, so the owner could not get his fiddle back. mutual mistake is a valid defense to a contract, so the owner could get his fiddle back. mutual mistake is not a valid defense to a contract, so the owner could not get his fiddle back. mistake of value is a valid defense to a contract, so the owner could get his fiddle back.