1. The plaintiff's appeal and the claims added by this court are all dismissed.

2. The costs of the lawsuit after the appeal are filed.

1. The plaintiff's assertion

A. On March 2015, the Plaintiff entered into a lease agreement with C Co., Ltd. (hereinafter “C”) and supplied temporary materials at the site of reinforced concrete construction works (hereinafter “instant construction works”) that were subcontracted by C from the Defendant during the construction of the Diplomatic Association located in Yeongdeungpo-gu Seoul, Yeongdeungpo-gu, Seoul.

After that, the lease agreement between the Plaintiff and C is terminated, and C around December 2015, the Plaintiff sought to recover the temporary materials that existed at the construction site of this case as the removal was made at the construction site of this case.

However, the Defendant requested that the Plaintiff continue to use the Plaintiff’s temporary materials for finishing works, such as Pesting and tin works. Accordingly, the Plaintiff supplied the temporary materials to the instant construction site from January 2016 to November 2016 according to a new agreement between the Plaintiff and the Defendant. As such, the Defendant is obliged to pay the fees for use and damages for delay.

B. Selectively, from January 2016 to November 201, 2016, the Defendant, without any title, is obligated to return unjust enrichment of KRW 53,476,831 and delay damages, as the Defendant used the Plaintiff’s temporary materials at the construction site of this case or used new temporary materials from the Plaintiff without any title.

2. As to each of the above arguments by the plaintiff, the following circumstances, which are acknowledged as comprehensively considering the overall purport of the arguments in the evidence Nos. 12, 7, 10, and 11 (including a serial number) as to each of the above arguments, i.e., (i) the plaintiff entered into a contract by setting up a temporary material lease agreement with C while leasing the temporary materials, and (ii) the plaintiff entered into a contract by preparing a detailed statement of transactions at the time of supplying the temporary materials to C at the construction site of this case, and (iii) the plaintiff and the defendant entered into a lease agreement for the temporary materials