Luo Cheng: Hello, I'm Luo Cheng, it's almost 2021, I'm 33 years old. Jessica: Annyeonghaseyo, I'm Jessica from Girls' Generation, it's almost 2009, I'm 20 years old. An unscientific accident allows him and her, separated by twelve years, to have a conversation. Information transcending twelve years directly changes his 'history,' effortlessly giving him an easier life. Resources transcending twelve years indirectly change her 'future,' allowing her to have a life without regrets.