1. The Defendant (Counterclaim Plaintiff) paid KRW 409,326,944 to the Plaintiff (Counterclaim Defendant) and its related amount from February 4, 2012 to February 5, 2015.

1. Basic facts

A. The Plaintiff is a company that operates a structure construction business, steel product construction business, steel product installation business, etc., and the Defendant is a person who engages in automobile repair business, parking service business, real estate leasing business, etc. under the trade name of “B” or “C”.

On July 2010, the Defendant designated the Korea Industrial Complex Corporation, the project implementer of the project for upgrading the structure, which was implemented in the Nam-gu Incheon Metropolitan City D pursuant to the Industrial Cluster Development and Factory Establishment Act, as an agent of the project for upgrading the structure, and concluded a contract for vicarious execution with the Korea Industrial Complex Corporation.

B. On March 1, 2011, the Defendant entered into a contract on the design, earth and sand, basic construction, and steel frame construction (hereinafter “instant contract”) with the Defendant, among the construction works necessary for the instant project, (hereinafter “e.g., the instant construction”).

According to the instant contract, the construction cost of the instant project is KRW 5,045,00,00 (including value-added tax; hereinafter the same shall apply) and the construction period is from March 1, 201 to August 31, 201.

C. On May 11, 201, tugboat construction entered into a subcontract agreement (hereinafter “instant subcontract agreement”) with the Plaintiff on steel-frame construction among the instant construction works (hereinafter “instant steel-frame construction”) (hereinafter “instant subcontract agreement”).

According to the instant subcontract contract, the construction price of the instant steel frame is KRW 1,501,50,000, and the construction period is from May 16, 201 to July 30, 201.

On May 18, 2011, KIG paid to the Plaintiff KRW 450,450,000 as advance payment in accordance with the instant subcontract agreement.

On the other hand, the Defendant, on June 20, 201, paid part of the steel materials price necessary for the instant construction to the Plaintiff.