In cases based on quasi-contract liability, the intention of the parties is entirely disregarded, while in cases of express contracts and contracts implied in fact the intention is of the essence of the transaction. In the case of actual contracts the agreement defines the duty, while in the case of quasi-contracts the duty defines the contract. Where a case shows that it is the duty of the defendant to pay, the law imparts to him a promise to fulfill that obligation. The duty which thus forms the foundation of a quasi-contractual obligation is frequently based on the doctrine of unjust enrichment. It rests on the equitable principle that a person shall not be allowed to enrich himself unjustly at the expense of another, and on the principle of whatsoever it is certain a man ought to do, that the law supposes him to have promised to do.
Defendant sold a home to decedent who ordered shrubbery from the plaintiffs to be placed on the property. The shrubbery was placed on the property but the decedent died before payment was made to the plaintiffs. Defendant sold the home with the shrubbery on the property. Plaintiffs then sued the defendant for unjust enrichment received from the increase in the value to the property because of the shrubbery.
Must Defendant pay the plaintiffs for the shrubbery based on quasi-contract?
The court stated that plaintiffs had no cause of action against defendant for unjust enrichment. To receive value for the shrubbery, plaintiffs had to sue decedent's estate. In the instant case the plaintiffs entered into an express contract with decedent and looked to him for payment. They had no dealings with defendant, and did not expect remuneration from it when they provided the shrubbery. No issue of mistake on the part of plaintiffs is involved. Under the existing circumstances we believe it would be inequitable to hold defendant liable. Plaintiffs' remedy is against decedent's estate, since they contracted with and expected payment to be made by Pendergast when the benefit was conferred. A plaintiff is not entitled to employ the legal fiction of quasi-contract to "substitute one promisor or debtor for another."