For every action, there is an equal and opposite reaction. What happens when your small action affects so many people's lives? how the butterfly effect plays an important part in all our actions forms the crux of N4.

When a clever, carefree gangster is recruited to help an overseas crime lord take down a rival, he is caught off guard by the moral dilemmas that follow.

A constable who prefers to mind his own business gets into a situation where he has to hide from a most-wanted gangster.

When a software engineer’s philanthropic efforts are curbed by corrupt authorities, he uses his own shrewdness and strength to fight for social reform.

Selvi falls in love with Vadivelu, a butcher. Realising that Vadivelu has to get his sister married first, Selvi helps him to find an ideal life partner for his sister.