Preston (defendant) was a silk merchant. Kingston (plaintiff) agreed to serve as Preston’s apprentice. At the end of that time, Preston was to sell the business to Kingston and a partner, who would continue to operate out of Preston’s home. Kingston promised to provide Preston with “sufficient security” and pay fair value for the business. Kingston sued for breach of contract, arguing that he was willing to perform his obligations under the contract but that Preston refused to sell the business. Preston argued that Kingston never provided the promised security. Kingston demurred. Kingston asserted that Preston was still obligated to transfer the business as agreed, because the parties’ mutual promises were independent of one another. Consequently, Preston could not rely on Kingston’s breach to avoid his obligations under the contract. Kingston argued that his non-performance merely provided a basis for Preston to bring a separate action against Kingston for breach. Conversely, Preston argued that the mutual promises made in their agreement were dependent on one another, and that Kingston’s failure to perform relieved Preston of his obligation to perform.