Spindler (defendant) agreed to sell shares of stock to Sackett (plaintiff). Sackett agreed to pay for the stock in installments on specific dates. Spindler agreed to deliver the stock in full to Sackett when Sackett had paid the final installment, which was due on or before August 15. Sackett paid the first installment on time but then fell behind in his payments. Sackett’s check for his final payment, though technically delivered on time, was denied by the bank for insufficient funds. On September 12, Sackett assured Spindler that he had the funds and would transfer them. Sackett’s attorney contacted Spindler’s attorney, and the two met on September 19 to discuss Sackett’s performance under the contract. At that meeting, Spindler’s attorney provided notice that unless Sackett paid the final installment, plus interest, by September 22, then Spindler would consider the contract breached and would refuse to complete his performance under the contract. Sackett failed to pay the balance. Spindler agreed to extend Sackett’s time for performance until September 29. Again Sackett failed to perform. On October 4, Sackett sent Spindler a telegram promising to perform under the contract. On October 5, Spindler's attorney informed Sackett by letter that, due to Sackett’s failure to perform, Spindler refused to sell the stock to Sackett. On October 6, Sackett offered to pay the balance for the stock in further installments. Spindler refused, but he stated that he would continue to honor the sale if Sackett would pay the full amount in cash or the equivalent. Sackett did not offer or tender cash or its equivalent. Sackett filed suit for breach of contract, claiming that Spindler’s October 5 letter constituted unlawful repudiation of the contract. Spindler filed a cross-complaint for breach of contract. The trial court held that Sackett’s refusal to pay the specified amounts by the specified dates constituted an unjustified breach of the agreement. The court entered judgment in Spindler's favor, and Sackett appealed to the California Court of Appeal.