Tomorrow With You is about a romance story between a time traveler and his wife. Yoo So Joon is a CEO of a real estate company, who has the ability to travel through time via a subway. Song Ma Rin is his wife and works as a photographer. So Joon foresees his future-self living miserably so he decides to marry Ma Rin in order to avoid that fate. As time passes, he learns to love her selflessly.