Before they became Dr. Miyawaki Sakura and Professor Lee Chaeyeon, the ones who introduced Professor Kang Hyewon and Professor Kwon Eunbi to each other, they were simply Sakura and Chaeyeon, a medical student and a graduate student trying to make it through University. (The prequel to One Plus 1 = 2)   

Unrequited love is something Jo Yuri knows a thing or two about, after all, she has been staring at Hitomi forever, whose eyes are elsewhere. Stuck in a tragedy for so long, Yuri sees all the signs of one and offers a helping hand.   But a hidden forest always remains waiting for her.