Despite being poor, Jung-Yuen is a happy teenager who gets on well with his family. During high school, he develops a crush on Shu-Yuen, a girl from his neighboring village, who is extremely smart, but reclusive with an odd personality. After they both begin university, Jung-Yuen, a medicine major, comes up with every excuse he can think of to get Shu-Yuen's attention, who locks herself away from the world in the library and her laboratory. After a lot of effort, Jung-Yuen finally succeeds in winning her heart. Mysterious equation is an uncanny love story about an optimistic doctor and a scientist who was ready to dedicate the rest of her life to science. Watch drama online for free.