"unjust enrichment, an equitable claim arising under common law that is available when there is not an adequate remedy at law. See Southtown Plumbing, Inc., 493 N.W.2d at 140. “To establish an unjust enrichment claim it must be shown that a party has knowingly received something of value, not being entitled to the benefit, and under circumstances that would make it unjust to permit its retention.”
"Similarly, here, even though the County follows the tax statute, by taking a windfall at Tyler’s expense, it took a benefit that in fairness and justice belongs to Tyler. Outside of Minnesota, at least one state high court has held that the doctrine of unjust enrichment could require government to return the windfall to a former owner. See Dean, 247 N.W.2d at 880. If this injustice is not fully remedied by Tyler’s constitutional and statutory claims, then unjust enrichment should provide relief. "