Four young men and women who are prejudiced against each other form a temporary team because of a mysterious email sent by a mutual friend who disappeared a year ago, and embark on a journey to find their friend with their own agendas. Along the way, they reasoned based on clues, overcame regional cultural differences and the obstruction of mysterious forces lurking in the dark, and even experienced life-threatening dangers. They traveled to four continents and four countries, and continued to expand the boundaries of their cognitive world during those little-known niche journeys. When they overcame various difficulties and finally met the friend they were looking for and learned the whole story, each of them reconciled with their past selves during each corresponding journey, took off their masks on their own initiative, and gained sincere friendship and love.
Purpose: A person should try his best to get the best reward in life.