Ota and his wife move in next door to the home I share with my wife Minaho. Because the two wives are best friends, we throw them a welcome party, where they get excited about the growing trend of documentaries in which couples swap spouses. I dismiss them as staged, but Minaho is intrigued, especially because the Ota house is far bigger than ours. I insist that swapping is out of the question, yet Minaho refuses to speak to me until I finally give in. We agree to exchange wives for three days...