SMS movie begins with Kichan (Bala) and Indumathi (Navya Nair) who study at the same college and just like any other story, their relationship starts with a fight and later on gets into romance.
Meanwhile, Kichan has two friends Soman (Anoop Chandra) and Satheeshan, Soman is a bit weird as he has the habit of sending vulgar SMS to just about any number he thinks and that too from the mobile of Kichan.
In this process, he ends up destroying the life of a girl (Kalyani) whose marriage gets called off and her father dies. Things like this continue until one day Indu sees a message in the mobile of Kichan and from then on trouble begins which finally leads to the death of Indu from the college terrace.
Special officer Robert Matthew (Mukesh) comes in for the investigation and realizes that there is something more than that meets the eye. His investigation begins and what happens from there forms the rest of the story.