1. All appeals filed by the Plaintiff (Counterclaim Defendant) and the Defendant (Counterclaim Plaintiff) are dismissed.

2. The costs of appeal shall be borne respectively by each party.

1. In the first instance court’s trial scope, the Plaintiff filed a claim against the Defendants for return of unjust enrichment, and Defendant A filed a counterclaim claiming payment of unpaid construction cost relating to each painting construction of this case. The court of first instance dismissed all the principal claim and partly accepted the counterclaim claim.

Therefore, the plaintiff appealed only against the claim of the principal lawsuit, and the part against the defendant A regarding the counterclaim was appealed, so the scope of the judgment of this court is limited to the part against which the defendant A appealed in the principal lawsuit and the counterclaim claim.

2. The reasoning for this Court to state this part of the basic facts common to the principal lawsuit and the counterclaim is as stated in Paragraph 1 of Article 420 of the Civil Procedure Act, and this part is cited by the main sentence of Article 420 of the Civil Procedure Act.

3. Determination as to the claim on the principal lawsuit

A. The Plaintiff’s summary of the Plaintiff’s assertion entered into a contract with the Defendants, who presented the minimum bid price for the first to fourth construction works, and agreed to pay the construction cost calculated through final settlement for each construction cost later.

However, at the time of conclusion of the contract for each painting work, the Plaintiff agreed with the Defendants to calculate the construction cost on the basis of the quantity, unit price, etc. stated in the evidence No. 8-1 to No. 4 (O. 4). As such, the amount of the construction cost reasonably calculated on the basis of this agreement, or the construction cost finally agreed with the Defendants, as stated in the evidence No. 2 through No. 5 (A. 127,390,000, Chapter No. 2, and Chapter No. 57,00,000, and Chapter No. 2, the Plaintiff stated that the “on-site settlement amount” was 54,00,000,000 won as to the over-site settlement of accounts for the over-site work. However, the Plaintiff thereafter stated that the “on-site settlement amount” was 54,000,000 won.