Aptharakshaka is the sequel of Apthamitra. This movie is all about the story of Nagavalli. A family in Mysore is disturbed by an ancient painting of Nagavalli. The members of the family Saraswathi (Lakshmi Gopalaswamy), Neetha (Bhavana) and Gowri (Sandhya) are psychologically affected by the presence of this painting and things have not been going too well in the house.
They decide to contact Ramchandra Acharya (Avinash), a magician. Acharya takes the help of Dr Vijay (Vishnuvadhan), a psychiatrist, to solve the problem. All directions point to the huge portrait of Nagavalli (Vimala Raman) and it is observed that the portrait is the cause for this.
The investigation also takes back to around 125 years when the king Vijayarajendra Bahaddur (Vishnuvardhan) used to live and how his enmity with Nagavalli has been going on since centuries. What happens from there forms the rest of the story.