Theory of Love

Khai goes back to his old ways of picking up girls. Third gets fed up and decides to move out of his house but hesitated when he defends him against an ex-girlfriend.

Third and Khai come closer during the Student Festival with Khai. However Third finds out it was all a plan on Khai's part to find out his (Third's) feelings.

Third finally gives up on his friendship and love after finding out that Bone and Khai both betrayed him. He fights with Khai and moves in with Two.

Khai and Third try to get back to being friends. However, Khai kissed Third while being drunk and called him by his girlfriend's name. This hurts Third even more and he starts to pull away from his friends. Khai starts regretting what he did and realized that he loves Third.

Khai tries to win back Third who is wary of him.

Khai is jealous and sad because Third now spends most of his time with a college senior Un. Khai and Third get into an argument and Khai has an accident.

Third takes care of Khai after his accident. Khai confesses his love to Third in front of everyone.

Third and Khai start dating secretly after Third agrees to give Khai one more chance. But Third is still insecure about his relationship with Khai.

Khai was kissed by a girl which Third saw. This lead to a huge misunderstanding between them. Third decided not to go on the beach trip and Two decided to accompany planning to let Bone and Khai go by themselves. At the grocery shop they run into Bone who tells them as Two had decided not to go he would let Third and Khai go by themselves unaware that Third was not going. This led to Khai waiting in the station by himself the whole day as he had promised his friends they would all go together.

Third and Khai reconcile after Third sees Khai's sincerity. However Third is still unwilling to take the final step as he doesn't fully trust Khai yet. Khai tries to change himself to convince Third that he is a new man.