Calvin and Audrey Bones (defendants) listed their ranch for sale. Dean Keller (plaintiff) made an offer to the Boneses’ real estate agent. The offer stated that it would become a binding contract upon execution by the Boneses. The offer also stated that it would expire by its own terms if not accepted by July 21, 1997, at 5:00 p.m. The Boneses signed the offer sheet and on July 21, at 4:53 p.m., faxed the signed offer to their agent. The agent informed Keller of the acceptance via voicemail at 5:12 p.m. Subsequently, the Boneses received another offer and declined to sell the ranch to Keller. Keller brought suit for specific performance. The district court granted the Boneses’ motion for summary judgment because the agent did not inform Keller of the acceptance until after the deadline. The court of appeals affirmed. Keller appealed.