Rameshan Nair (Mohanlal) is an intelligent man who helps with his son's education most fervently. His wish is to make his son an IAS, a feat he himself could not achieve. He is employed in the state secretariat and leads a very happy family with two children and wife.

Ramheshan Nair forgets the nickname he used to call his childhood sweetheart. He tried hard to recollect but fails. Then one day he goes to the office with tomatoes and other vegetables which must have been bought for home in the evening.

Alzheimer's is a disease of the brain. Dementia is its main feature. Dementia is the loss of intellectual functions (such as thinking, remembering, and reasoning) of sufficient severity to interfere with a person's daily functioning. Worldwide millions of people are affected by this slow progressing and terrible disease.

Transformation of Rameshan Nair from a healthy, happy individual to a man gradually forced to a vegetative state by Alzheimer's disease has been very frightening to watch. This transformation has been enacted with great brilliance by versatile Mohanlal.

Second half of the movie can be only watched with a stunned mind. If you try to put yourself in the characters position, it is enough to shake the toughest of souls.

Lekha (Meera Vasudev) in the role of Rameshan Nairs wife and his son Manu (Arjun) both performed exceptionally well. Director Blessys debut film Kazhcha has been a great success. Thanmatra has almost outshined his debut.

Brilliantly told, in a career best acting by versatile Mohanlal and with the magic of our relatively new director Blessy, Thanmatra deserves to be called as one of the finest Malayalam movies ever.