Kendrick v. Barker
Supreme Court of Wyoming
15 P.3d 734 (2001)
Kendrick (plaintiff) sued Barker (defendant) for injuries from a collision with his tractor-trailer, and her attorney accepted a mediator-proposed $40,000 settlement releasing all claims. Kendrick later tried to back out, hiring new counsel, after learning she'd been diagnosed with a closed head injury and worrying the settlement wouldn't cover future medical costs; Barker moved to enforce the settlement. Kendrick testified she understood the offer was meant to fully settle her claims without any reserved exceptions, but argued mutual mistake precluded enforcement given her later diagnosis; the trial court disagreed and granted Barker summary judgment.
Whether a contract is voidable on grounds of mutual mistake if both parties independently make a common mistake as to a basic assumption of the contract at the time of entering the contract.