Hassan Sanati and Fatane Sanati (defendant) were married and had two children (defendants). Mr. Sanati opened an account with Bank of America (plaintiff) in London with funds derived from the Sanatis’ bank accounts and real property. Subsequently, Mr. Sanati left the family. Mr. Sanati instructed Bank of America in London to send the interest that accrued monthly on the London account to an account that he held jointly with Mrs. Sanati at a Bank of America in California. Bank of America in London erroneously sent the entire principal amount of Mr. Sanati’s bank account to the joint account in California. Mrs. Sanati and the children withdrew the full amount from the joint account. Bank of America requested reimbursement from the defendants for the erroneous payment. The defendants refused. Bank of America sued, seeking restitution. The trial court granted summary judgment in favor of Bank of America. The defendants appealed.