A. 1) The Plaintiff is a corporation whose business purpose is an information and communications construction business, etc., and Defendant A Co., Ltd. (hereinafter “Defendant A”).

Defendant B Co., Ltd. (hereinafter “Defendant B”) is a corporation with the business purpose of civil engineering and construction, etc., and Defendant C is a person who actually operates Defendant A and B.

2) Defendant A received a contract from D for the construction of the instant collective housing E-ground (hereinafter “instant collective housing”) (hereinafter “the instant building”). The Plaintiff, among the entire construction works from Defendant A on September 23, 2015, constitutes the “the instant initial construction works” (hereinafter “instant initial construction works”).

B) From August 29, 2015 to February 2, 2016, D was awarded a subcontract for the construction period of KRW 178 million (including value-added tax) of the construction amount. D directly performed lighting construction during the first construction period.

4) On February 2016, the Plaintiff completed the remainder of the instant construction, excluding lighting construction, and obtained approval for use of the instant building on or around April 2016. Defendant A paid the Plaintiff a total of KRW 120 million as construction cost. Defendant A paid the Plaintiff KRW 50 million on April 6, 2016 (including value-added tax) with the payment guarantee of Defendant B and Defendant C, within seven days after the completion of the construction (hereinafter “instant payment rejection”).

Since then, the Defendants paid 2,5830,000 won out of the instant payment note to the Plaintiff.

[Ground of recognition] Facts without dispute, Gap evidence Nos. 1 through 3, Eul evidence No. 1, witness F's testimony, the purport of whole pleadings

B. According to the above facts of recognition, the defendants jointly seek the amount of KRW 31 million payable to the plaintiff (=5,6830,000 won - 2,5830,000 won) and the amount of the instant payment after the due date.