Ajit Thomas (Dileep) is an acclaimed investigative television anchor and producer with a leading channel 'Calcutta News', and is the son of a former footballer who grew up in Kolkata. His team at the channel includes news assistant Smita (Vimala Raman), and anchors Aruna (Manasa) and Sheela (Brinda). Ajit is a lovable guy who lives in a flat with his mom and sister and is active member of the Malayalee Samajam led by a comical president (Innocent) and his wife ( Bindu Panickkar) One day Ajit bumps into a newly married Malayalee couple while on work in a tram, but the guy is hostile when he tries to introduce himself as a Mallu! However, while editing the news, he is shocked to find that an unidentified body found near Kalighat resembles the rude guy he met in the tram.
Ajit's investigative nature comes into the fore as he goes about finding the mystery behind the brutal murder of the guy. The guy was Hari (Indrajith), who had married an orphan Krishnapriya (Meera Jasmine) from Pattambi and brought her to Kolkata, before his brutal murder. Krishnapriya is unaware of her husband's job or what he does for a living and is shattered to know about his death. However hope floats into her life after Ajit sort of becomes her protector and also gets attracted to her for her innocence and their mutual love for music.
Meanwhile Ajit finds that there is something rotten and discovers that Hari was one of the henchman in a sex racket that traps innocent girls and sells them to a one-arm bearded guy (Kathal Krishnamoorthy) who operates from Sonagachi, the largest red-light area in eastern India! Ajit along with his friends try to unravel the sex racket using their television channel, which leads to the bearded guy kidnapping Krishnapriya and taking her to his den in Songachi! Can Ajit in hot pursuit get through the maze of nightmarish and confusing alleys and by-lanes of Songachi to reach his lady love?