1. The part of the judgment of the court of first instance against the principal lawsuit shall be revoked.

The plaintiff (Counterclaim defendant)'s main claim is dismissed.

2...

A principal lawsuit and a counterclaim shall be deemed simultaneously.

1. Basic facts

A. After receiving a contract for the “A project” ordered by the Young-gun (hereinafter “instant project”), the Defendant agreed to perform the instant project en bloc with the Plaintiff during the period from December 16, 2013 to October 11, 2014, with each of the instant projects set forth between the Plaintiff and the Plaintiff as the subcontract price of KRW 300,000,000 (value-added tax separate) and the construction period from December 16, 2013 to October 11, 2014, and the Plaintiff entered into an agreement to perform the instant project in the name of the Defendant (hereinafter “instant subcontract agreement”).

B. On December 11, 2013, the Defendant concluded a contract for the instant construction work with the Sung-gun for a fixed period from December 16, 2013 to October 11, 2014 with respect to each of the instant construction works, and subsequently changed the contract by setting the construction cost of 638,50,000,000, and the date of completion on November 30, 2015.

C. The Plaintiff and the Defendant did not have any separate agreement on the construction cost under the instant subcontract agreement, and the Plaintiff commenced the instant construction work under the Defendant’s name and completed the instant construction work at the time of completion.

After the Plaintiff completed the instant construction project, on December 2015, 2015, the Defendant demanded the Defendant to settle the subcontract price for the instant construction project, and the Defendant demanded the Defendant to settle the subcontract price at KRW 439,89,300 for the instant construction project. The Plaintiff raised an objection to the purport that the settlement of subcontract price at KRW 439,89,30 for the instant construction project would be unilaterally damaged by the Plaintiff. Accordingly, the Defendant demanded to adjust the subcontract price at KRW 458,657,460 for the purpose that the settlement of the said amount would be unfair. However, the Plaintiff refused such request and did not reach the settlement agreement.

E. Meanwhile, an agreement prepared at the time of the instant subcontract agreement (No. 1, hereinafter “instant agreement”).