A young 16 yr old girl, Zhu Ying Tai, managed to convince her parents to send her to college at Hangzhou on the condition that she went in the guise of a man. Along her journey to the college, she met 17 yr old Liang Shan Bo who was also attending the same school as her. They became sworn brothers and studied for 3 years together. Over this period of time, they formed a strong friendship. Ying Tai gradually fell in love with Shan Bo, who being a bookworm, never did discover what she was despite coming across a couple of oddities. When she was summoned home by her father, Ying Tai revealed the truth to her headmaster's wife. Ying Tai requested that she be the matchmaker for her and Shan Bo and gave her a jade pendent as a token to be handed to Shanbo.
Shan Bo walked with Ying Tai for 18 miles to send off his sworn brother. She tried several times to hint to him her identity during the journey but to no avail despite insulting him twice in her exasperation with his denseness. Finally, she found a way and got his consent to matchmake him to her "twin sister". She exhorted him to seek out his fiancee soon before they reluctantly took leave of each other at the pavilion where they first met. Upon returning to school, Shan Bo was restless and could not concentrate on his studies in the absence of his sworn brother. Seeing this, the headmaster's wife told him about Ying Tai, gave him the jade pendent and bade him to go propose to her.
The joy of the reunion of the two came to ought when Ying Tai told Shan Bo he was 3 months too late. Her father had already betrothed her to the frivolous son of the powerful and wealthy Ma family. Shan Bo, who was already ailing, was deeply grieved. He returned home and his health steadily deteriorated until he became seriously ill. Several days before her wedding day, he asked to see her again. When his servant returned instead with a token from her, it was the final blow. He sent his servant to Ying Tai with a last gift and died. Ying Tai was stricken ed with sorrow and forced her father to come to a compromise : to allow her to visit Shan Bo's tomb on the way to her betrothed home or she would not marry. At the tomb, she swore her undying love for Shan Bo and that if they could not be together in life, she would rather be with him in death. A tornado sprang up and an earthquake split the tomb in two whereupon Ying Tai threw herself into it. The whipping winds covered the tomb with sand. When the winds died down, two butterflies were seen soon after, flitting away to the heavens.