A. The Plaintiff is a company that received a contract for construction for the said urban development project from the E Urban Development Association (hereinafter “instant Association”) that implements an urban development project in the Northern-gu D branch of the Port-si.

B. The Defendants jointly subcontracted part of the construction work in a complex (excluding electrical construction; hereinafter “instant subcontracted construction”) among the construction work for the said urban development project (the construction work in a complex and the construction work outside a complex) from the Plaintiff.

C. On August 16, 2013, the Plaintiff entered into a construction subcontract agreement with the Defendants regarding the instant subcontracted project with the amount of KRW 6,941,00,00,000. On March 7, 2014, the Plaintiff entered into a construction subcontract agreement with the Defendants, which set the contract amount of KRW 7,440,200,00, and paid the Defendants the total amount of KRW 5,685,637,186 as the subcontract price up until then.

(including direct payments for re-subcontracts by the Defendants) and (d) the portion paid as land allotted by the Defendants in recompense for development outlay.

The contract for construction works between the Plaintiff and the instant association was terminated on July 15, 2014 due to the notice of termination of the instant association. Around that time, the instant subcontract was suspended.

[Ground of recognition] The fact that there is no dispute, Gap evidence 1-2, Gap evidence 2-1, Gap evidence 9, Gap evidence 10-1 and 2, and the purport of whole pleadings

2. The plaintiff's assertion

A. The Plaintiff is obligated to pay the Defendants, who performed the subcontracted project in this case, the construction cost according to the ratio of the construction work performed by the Defendants upon subcontracting.

However, KRW 5,685,637,186 paid by the Plaintiff to the Defendants as the payment for the subcontract price is paid in excess of KRW 2,038,075,361, which constitutes unjust enrichment.

Therefore, the Defendants are obligated to return to the Plaintiff the amount equivalent to the construction cost received in excess as above.

(b) claims for damages;