"Marriage wasn't supposed to be like this! I want to go back to those days and start my life over!” The story begins when the protagonist suddenly travels back in time and replaces his wife. In the fifth year of marriage, when both the husband and the wife are no longer able to care for one another like the early years, they have only one common way of thought.” Why did I marry this person…? While realistically and comically portraying the frustrations and regrets that everyone has in their marriage, the story is told through the protagonist, who has achieved a miraculous life after his shocking wish ‘to return to that day’ which somehow comes true. "What kind of person is important to you? " "What does it mean to spend a lifetime with someone else?" The story pursues such an universal theme for couples…