An astronomy student's scientific curiosity leads her to investigate mysterious love letters emerging from an unexplained white hole in her ceiling.

Son Da Eun, 17, is the youngest of three sisters. From an early age, she and her sisters would spend their time reading romance-themed comics and novels, and Son Da Eun would spend her nights dreaming of finding true love. Her family moves to the South Korean capital, Seoul, and she finds herself living next door to a handsome high schooler named Kim Seung Hyu. He is charming and attractive and she feels that perhaps he might be her first true love.