1. The plaintiff's appeal and the conjunctive claim added by this court are all dismissed.

2. After an appeal is filed.

1. The reasoning for this part of the judgment of the court is the same as that of the corresponding part of the judgment of the court of first instance, and thus, this part is cited by the main text of Article 420 of the Civil Procedure Act

2. The plaintiff primarily entered into a contract with the plaintiff and the defendant as KRW 123,00,000 per square year with the contract price of this case as KRW 3,00,000 per square year (=3,000 per square year x approximately KRW 40,000 per square year x KRW 3,00,000 among them), and the defendant paid only KRW 90,000 among them, and the defendant paid the remaining contract price of KRW 33,00,000 and delay damages therefor to the plaintiff, and the defendant actually required KRW 141,718,000 as the total construction cost of this case as well as KRW 141,718,00 as the ancillary construction cost of this case. Thus, the defendant also has the obligation to pay the plaintiff damages for delay from the return of unjust enrichment of KRW 51,718,000 among them.

On the other hand, the Defendant asserts that the Plaintiff and the instant construction cost of KRW 90,500,000 per square year (i.e., KRW 2,500,000 per square year x approximately 40 x 10,000 per square year - the Plaintiff’s discount amount of KRW 10,000 per square year) have been paid in full, and that the Plaintiff’s claim is groundless.

3. The following circumstances acknowledged by the overall purport of each statement and pleading of evidence Nos. 2 and 3 (including paper numbers) as to the primary claim: (i) the parties to a construction contract agree to simultaneously implement the balance of the construction work and the delivery of the completed construction work objects; and (ii) the Plaintiff delivers the house completed without receiving any construction cost any more than five months after the payment of the construction cost was made by the Defendant on April 26, 2016; (iii) the Defendant completed the registration of preservation of ownership on the said house on September 26, 2016; and (iv) the Plaintiff completed the registration of preservation of ownership on the instant building after the Defendant completed the registration of preservation of ownership due to the lack of funds.