Arulnithi walks out of a house at middle of the night. Simultaneously, several police officers assemble at the venue for an alleged murder investigation. The officers corner Arulnithi under suspicious circumstances and enquire him about wandering around a crime scene at an odd hour. He defends himself by stating that he was returning back from watching a night show. 

However, they capture another eye witness who vows that Arulnithi was the last man to exit the house. The officers then try to arrest Arulnithi, who somehow escapes their clutches. The story then moves to a flashback portion, where Arulnithi is shown as a call taxi driver. He is also in a happy relationship with Mahima Nambiyar who is a nurse. 

Meanwhile, Mahima befriends Ajmal as he helps her to tackle a horrible eveteasing situation. But, a while later he begins to hit on her in an uncomfortable way. She immediately cuts ties with him, yet he finds a way to torture her. She then opens up about the seriousness of the issue to Arulnithi. Meanwhile, Chaya Singh attempts to take her own life in front of the couple. 

Arulnithi saves her life by talking her out of committing suicide. Chaya Singh then breaks down and says that she is being mentally tortured by Ajmal. Arulnithi looses his patience and decides to beat up Ajmal. He breaks into his house, only to witness an already dead women lying on floor. The rest of the plot revolves around how he escapes the situation. 

Arulnithi has pulled of his character well and has delivered a natural performance. Especially during the romantic and actions sequences. This is the first time Ajmal has taken up a role with negative shades, and he has aced it. Mahima Nambiar had done her given part neatly. And so has, other female lead characters; Chaya Singh, Suja Varunee and Vidya Pradeep. 

Other supporting actors such as Aadukalam Murugadoss, Lakshmy Ramakrishnan, Anandaraj Selvaraj, and John Vijay have also delivered a decent performance. 

Debutant MU Maran has attempted to make an intense thriller which has all the essential elements in one such movie. The screenplay is well woven a crime story with a lot of twists in unexpected places. However, the director could have gone easy with complicating the script as it does get confusing at several places, which all ties up towards the climax of the movie. 

Sam CS background score is on point, and keeps the viewers engaged to the script. Aravinnd Singh's cinematography skills come to the fore, and he has shot well. 

In short, Iravukku Aayiram Kangal is enthralling to watch.