Hikari and Noa are mom friends who live in a luxury apartment and are married to famous people. They both have very strong sexual desires and are always talking about their sexual frustrations. Then they find out about a secret party. It's a members-only event for the wealthy, and participants wear masks so their faces won't be revealed. They decide to attend, and a strange sight unfolds before their eyes. It's their first time seeing the world of SM, and their first experience of the ultimate masochistic pleasure. They discover that various sexual acts while restrained can be extremely pleasurable... A new door has just opened for these two.