Eri is an almost perfect student (if math didn't exist). After a botched midterms, she goes to beg her professor for a second chance. However, on the way there she finds a strange boy, who also happens to be looking for the professor. Despite herself, Eri agrees to help, and the two find their paths entwined forever.
As the two grow close, there's only one thing Eri needs to keep in mind; love blooms and dies in the spring.