Vladimir Constructions contracted to build the Petersons a house for $50,000. When Vladimir began digging the foundation, it hit bedrock, which was highly unusual in that area. Vladimir told the Petersons that it required an extra $5,000 to build the house. The Petersons agreed, but when the house was done, refused to pay Vladimir any more than the original contract price. What can be the outcome if Vladimir sues the Petersons for the extra $5,000 and why?