Vadakkunokkiyanthram movie is all about Thalathil Dineshan (Sreenivasan) who is a man who runs a printing press. He is a man laden with a lot of insecurities, owing to his lack of height and dark complexion. His life spirals out of control after his marriage to Shoba(Parvathy). His insecurities gets heightened by the fact that his wife is exceptionally beautiful. Initially he is over-protective of his wife, which worsens his relationship wth his brother(Baiju). He felt challenged by the charm and wit of his brother, which eventually leads to the eruption of a feud in the family.
Dinesnan gradually resorts to tactics which ,he feels,would enable him to earn the respect and admiration of Shoba.He finds a new confidante in Thalakulam Sir(Innocent),who gives him reckless advices. He starts drinking, believing that its the symbol of machismo. He mugs up the jokes in the magazine and delivers them to his wife in a monotonous manner, so as to appear witty. But all these attempts turned out to be pure antics and he made a mockery of himself.
Shoba who is an archetypal Indian wife, is very much devoted to the husband and cannot gauge the reason for Dineshan's eccentric behaviour. He gradually gets infected with paranoia and starts suspecting his wife. That forces him to threaten the brother(Lalu Alex) of Shoba's friend, whom he suspects to have an affair with her. Things go out of his control when Shoba learns about everything. He is even admitted to mental hospital, following some incidents from extreme paranoia, and after a brief treatment he appears to be a changed man.
Dineshan wins his wife back from her parental home assuring her love and care. Now all seem to be fine with them, but again in the dead of the night when his wife is asleep he will start suspiciously looking out in his backyards for a secret lover of his wife, almost like a Hitchcock ending. Thus Dineshan lives up to the name of the movie 'Vadakkunokkiyanthram' (compass) and like a compass, what ever way his life turns he will remain oriented towards inferiority complex and suspicion.