A contract is a real agreement between two or more parties, but a Quasi-contract is not an agreement but resembles an agreement or a contract. Under a contract, both parties give their consents freely, while under quasi-contract, there is no consent of either of the parties, as it is not voluntarily made. Quasi contracts are legally enforceable because the agreement is constructed in a court of law.
A contract has some essentials which include offer and acceptance, without these two essentials a contract cannot be enforced in the court of law. However in order to uphold the principles of equity, justice and good conscience there can exist situations where despite of the presence of the essentials of the contracts the contracts are considered enforceable in the court of law. These contracts which are enforceable under special circumstances which apparently do not satisfy the conditions of contracts but seem to be contracts are known as quasi-contracts, where quasi means apparently but not really.
The concept of quasi-contracts comes into existence due to the principle of Nemo Debet Locupletari ex aliena Jactura which means that no one can benefit from other persons loss, due to which any liability arising out of the situations mentioned in 68 to 72 is considered as a quasi-contract, so that the anybody cannot unjustly enrich at the expense of someone’s loss.
Section 68 to 72 accounts for these special circumstances, however, the question about quasi-contract being enforceable in the court despite of a presence of an agreement is because in certain situation like implied responsibility after finding goods, paying for necessities, paying for the goods obtained by coercion, person enjoying benefit from anybody non-gratuitous act etc another person unjustly gets advantage which is not right justice to the other party., thereby courts allow the enforceability of a contract without agreement in certain conditions.