After ruining an incredibly expensive experiment, lab assistant Seon Seorim finds himself facing a mountain of debt. Fortunately, he can clear it all by working as a spy in Gong Woon's lab as a product tester. Little does he know, however, that Gong Woon has transitioned to creating more... adult-centered products and toys. Can Seorim endure the rigorous tests long enough to clear his debt?