1. The plaintiffs' appeal is dismissed.

2. The costs of appeal are assessed against the Plaintiffs.

Purport of claim and appeal

The first instance court.

1. The reasoning of the judgment of the court of first instance cited by the main text of Article 420 of the Civil Procedure Act, in addition to adding the following judgments to Chapter 4, Chapter 19 of the judgment of the court of first instance, is the same as the entry of the reasoning of the judgment of the court of first instance.

2. The plaintiffs asserts that the claim in this case is not a claim for return of unjust enrichment, but a claim for damages against the act of nonperformance or tort committed by the same sub-construction company by compulsory execution in violation of the agreement in this case, and that the lawsuit seeking return of unjust enrichment and the lawsuit claiming return of unjust enrichment do not affect the res judicata.

However, as seen earlier, “the res judicata” does not allow a subsequent suit identical to the subject matter of a prior suit which has res judicata, and even if the subject matter of a prior suit is not identical to the subject matter of a prior suit, if the judgment on the subject matter of a prior suit is prior to or contradictory to the judgment on the subject matter of a prior suit, the subsequent suit does not allow any assertion different from the judgment on the prior suit in the prior suit (the case of the first instance trial). Thus, the subsequent suit does not lead to the effect of res judicata merely because the subject matter of a prior suit is different from the subject matter of a prior suit.

3. The decision of the court of first instance is justified, and the plaintiffs' appeal is dismissed as it is without merit. It is so decided as per Disposition by the assent of all.