Pretty-faced art student Nong Hin is admired and approached by many. However, Hin isn't interested; he already has someone he likes, someone he's been waiting for forever. Then he meets Phayu. Phayu is his senior, an engineering student attending the same university. Phi Phayu flirts with Hin shamelessly.

Grey Rainbow tells the love story of Nuer and Porsche. Nuer is the son of the owner of an elephant camp while Porsche is a law student. In university, they were dormitory roommates and close friends, each fighting against the feelings that one has for the other.

Gun Tossakan is a very bright and tall medical faculty freshman who has been in love with the popular third-year Engineering major and head hazer, Bar Sarawat, ever since he was in high school. Although at that time Gun was unable to confess his feelings because of the promise he made to his mum to not date until he passed high school, once he enters university fate has very different plans for him. The world is small, and a university is smaller. Being popular students at the same university leads Gun and Bar to collide with each other again and again until Gun succeeds in wooing Bar. Or maybe Bar too has a confession to make?