1. The Defendant (Counterclaim Plaintiff) paid KRW 14,440,074 to the Plaintiff (Counterclaim Defendant) and its amount from August 13, 2013 to July 17, 2015.

A principal lawsuit and a counterclaim shall be deemed simultaneously.

1. Basic facts

A. On March 7, 2012, the Plaintiffs: (a) concluded a contract with the Defendant for the construction of the instant building; (b) the construction cost of KRW 2.827 billion (including value-added tax) and the construction period from March 7, 2012 to November 10, 2012; and (c) concluded a contract with the Defendant for the construction of the instant building (hereinafter referred to as “instant building”); and (d) the construction cost of KRW 2.827 billion (including value-added tax).

After that, several consultations have been made between the plaintiffs and the defendant regarding the increase in the construction cost, and finally, the construction cost was changed to KRW 3.146 million.

(hereinafter referred to as the “instant construction contract” in total, including the original contract and the modified contract.

After completion of the instant building, the Defendant transferred the instant building to the Plaintiffs, and the instant building was approved on May 23, 2013.

[Reasons for Recognition] Unsatisfy, Gap evidence 2 and 14, each of the statements (if available, each number shall be included; hereinafter the same shall apply), the purport of the whole pleadings

2. The parties' assertion

A. The Plaintiffs were awarded the instant construction contract to the Defendant with KRW 3.146 billion, but among them, KRW 3,0810,000,000, which would be KRW 3.115.19 billion if the Plaintiffs were to remove unfairly increased.

Here, if the plaintiffs filed a claim for the construction cost against the plaintiffs transferred by the defendant to the defendant in lieu of repayment of their obligations to subcontractors, the unpaid construction cost (3,115,190,000 won - 1,803,803,307,140 won - 1,066,450,690 won) remains.

If the above amount plus KRW 168,887,140, which the plaintiffs borrowed from the defendant on May 30, 2013, and then set off or deducts the debt of KRW 459,569,384 below to the plaintiffs against the defendant, the obligation of the plaintiffs to pay the construction cost to the defendant is all extinguished. Rather, the plaintiffs are the plaintiffs' claims and claims as of December 11, 2014.