Unjust enrichment requires restitution where a benefit retained at another's expense would be inequitable to keep. The doctrine of unjust enrichment imposes restitution where a defendant has received and retained a benefit that, in justice and equity, belongs to another. Its elements are: enrichment by receipt of a benefit, enrichment at the claimant's expense, and that it would be unjust to permit retention. Liability may arise even if the recipient was not a wrongdoer, and courts have broad powers to grant restitution to prevent inequitable retention.