A. The Plaintiff is a person engaged in the construction business, etc. under the trade name of C, and the Defendant is a corporation that runs the business of manufacturing steel structures, and the non-party limited liability company EPa (hereinafter “EPa”) is a corporation that engages in the business of manufacturing metal products.

B. On March 11, 2016, the Defendant concluded a construction contract with Espia to subcontract the manufacture and supply of gas treatment facilities to KRW 805,200,000 for the construction cost during the aforementioned D installation work with Nonparty C’s environmental service company (hereinafter “Copul environmental service”). On May 16, 2016, the Defendant concluded a construction contract with Nonparty C’s and Espia to subcontract the manufacture and supply of tank products to KRW 100,20,000 for the construction cost (hereinafter “each of the instant construction works”).

C. On May 12, 2016, EPA entered into an agreement on the assignment of claims with the effect that EPA will transfer KRW 100 million out of the construction price claims against EPA against the Defendant of EPA (hereinafter “instant agreement on the assignment of claims”) with the limited liability company (hereinafter “SP”) in order to perform each of the instant construction works, and on May 23, 2016, to EPA’s transfer of KRW 345 million out of the construction price claims against EPA against the Defendant (hereinafter “instant agreement on the assignment of claims”).

C. On July 8, 2016, the Plaintiff, the Defendant, and Espia agreed to waive each of the instant construction works with respect to each of the instant construction works, and to pay KRW 80 million to the Plaintiff as the price for the purchase of piping materials (hereinafter “instant agreement”). The main contents of the instant agreement are as follows.

Agreement “A”. B.