1. The plaintiff's claim is dismissed.

2. The costs of lawsuit shall be borne by the Plaintiff.

1. Basic facts

A. On April 26, 2017, the Defendant ordered construction from C Corporation (hereinafter referred to as “Nonindicted Corporation”) with respect to the installation of Manoday within the d basin.

On September 2017, the Defendant entered into a contract for construction works (including value-added tax) with respect to construction works for platform construction (hereinafter “instant platform construction works”) among the construction works and the construction works for the installation of platform platforms (hereinafter “instant platform construction”) which is KRW 423,500,000.

On September 4, 2017, the Defendant concluded a subcontract with E (hereinafter “E”) on September 4, 2017, which is KRW 327,800,000 (including value-added tax) for the new construction of the platform of this case.

(F) On September 2017, E entered into a sub-subcontract with the Plaintiff (F) on the remainder of the construction works, excluding electricity storage works, among the new construction works of the platform of this case.

B. As to the new construction of the platform of this case, there was an additional construction work due to a design change, etc. after the conclusion of the said contract.

On December 2, 2017, the Defendant entered into a contract to change the construction cost to KRW 684,887,55 (including value-added tax, and KRW 619,987,555 in the case of excluding the part of the toilet works without a line) with respect to the non-party construction and the new construction of the platform of this case.

C. Around December 2017, E presented a written estimate in the name of the Plaintiff, ① as a written estimate in the name of E, the construction amount of KRW 150,00,000 (excluding value-added tax), and among which KRW 60,000,000 is presented to the Plaintiff (F), a written estimate in which the direct payment is made to H architect office, and ② a written estimate in the name of the Plaintiff, and ② a written estimate in the name of the Plaintiff, with the construction amount of KRW 313,625,050 (excluding value-added tax).

After January 1, 2018, the Defendant drafted a contract agreement on construction works for the instant platform (a price of KRW 150,000,000 for construction works, and a separate value-added tax) with E, retroactively as of September 1, 2017, and ② the platform between the Plaintiff and E on January 19, 2018.