Singer agreed to perform a two-hour set every Friday night at Restaurant for a period of six months, or 26 performances. Restaurant agreed to pay Singer $13,000. After the first performance, Singer asked to be paid $500 for the first performance. Restaurant refused, insisting it had no duty to pay Singer until all 26 performances were complete. Assume there is no state law concerning wages that governs the contract. If Singer sues for breach of contract, who will win