Tiffany Hwang is a rather plain, ordinary looking girl who's grade are top of her class.. One day, she is approached by the super popular Jessica Jung, who claims she want to be friends.      

It's about of groups of friend who have customized their microwave into a device that can send text messages from the past.   As they perform different experiment, an organization named SM who has been doing their own research on time travel tracks them down and now the characters have to find a