Season 1 of Left Me Behind premiered on October 16, 2015.

Perapol is usually “invisible” to everyone until he meets a girl at school, Khemsuda, who befriends him right away. The two develop a good friendship throughout school year until Khemsuda had to move to a different school. Before she left, she gave Perapol her contact information and the two never saw or heard from each other again. Now grown up, the two coincidentally met again at a pub where Perapol and his friends hang out at.