In 2050, the organization Alice was formed as a way for humans to travel into another time and parallel world. Soon, however, the “Book of Prophecy” was discovered which predicted the end of travelers. In an attempt to prevent the book from falling into the wrong hands, Alice sends Yoo Min Hyuk and Yoon Tae Yi to 1992 to retrieve it from the last known keeper of the book. It was during this mission that Tae Yi realized she was pregnant with Yoo Min Hyuk’s child and decided to stay to raise their child and hid from Yoo Min Hyuk by changing her name to Park Sun Young. Park Jin Gyeom, the son of Park Sun Young, is a successful detective in 2020. His path crossed with the Yoon Tae Yi of this world, a physics professor specializing in quantum and temporal mechanics, and who looks exactly like his mother. The meeting of Park Jin Gyeom and Yoon Tae Yi was the start of their journey into rediscovering the Book of Prophecy and their search for answers.