Two couples were matched through a swapping service provided by a certain company. - Although the reasons for registering were different, the compatibility was great. - The first swapping session takes place in front of each partner. - There is a tense atmosphere at first, but that quickly changes. - By actually having sex and watching it, you will be enveloped in excitement and pleasure that transcends any sense of immorality. - Captivated by the charm of swapping, the two couples gradually immerse themselves in extreme play. - They pursue further stimulation by using toys or having sex in places where others may be able to see them. - This is the true story of two swapping couples who get involved in immoral activities themselves and get deeply involved.