Vanegas and several other employees (the employees) (plaintiffs) worked as at-will employees for American Energy Services (AES) (defendant). An AES representative orally promised the employees that if AES was sold or merged with another company, the employees who were still employed at AES would together receive five percent of the value of the sale or merger. AES was sold, but the company refused to pay the remaining employees their proceeds from the sale. The employees who were still employed at AES sued for breach of an oral contract. AES moved for summary judgment, arguing that the agreement to pay the employees was illusory. The trial court granted summary judgment for AES, and the court of appeals affirmed. The employees appealed.