Unaware that Lakshmi is his friend Anand's fiancee, Karthik ends up sending her a love letter. Things turn ugly when Anand doubts Lakshmi for infidelity after getting married to her.

Aasaiyil Oru Kaditham is a story about Karthik (Prashanth) who falls in love with Lakshmi (Kausalya) without knowing the fact that she is his best friend Anand's (Anand) fiance. Things turn ugly when Anand starts suspecting Lakshmi for infidelity after marriage.