Thedi Vandha Mappillai

The movie begins, whereby Solaimalai eldest baby daughter is kidnapped. The baby eventually is saved by passerby and raised as his own daughter. Solaimalai wife, Chellam unable to bear her eldest baby daughter lost, falls down from stairs and blame Solaimalai for his sins by murdering his boss. Solaimalai a.k.a. Pasupathy (Major Sundarrajan)’s boss (B. R. Panthulu) is shot by Samundi, but the blame falls on Pasupathy. The surviving boss sends away his wife Parvati Ammal (M. V. Rajamma) and son Shankar into hiding, fearing his family's fate. But before breathing his last, the boss learns the truth and entrusts in Pasupathy the task of finding Parvati and Shankar and handing them their rightful family assets. He also change his name from Solaimalai to Pasupathy fearing Samundi may revenge or murder him. Chellam hearing the truth finally hopes Pasupathi finds the true heir of his boss property heir, succumbs to her injury and dies.

Several years later, Shankar (MGR), now a grown up youth, learns of the injustice committed to his father (B. R. Panthulu), and heads out to Chennai in search of his father’s murderer, thinking as Solaimalai. However he don't know Solaimalai another name Pasupathi. Pasupathi vows to find Parvathi and Shankar and vows to get married of Uma and Shankar. Shankar meets Pasupathy’s daughter, Uma (Jayalalithaa) and falls in love with her, without knowing her background. It is shown to us, Pasupathi eldest daughter, Jaya (Jothilakshmi) a raised as Thirumangai by the passerby (now turned as blind) is shown as a pick-pocket who only steals 1 rupee in day. Suresh gets acquainted with Karpagam (Cho Ramaswamy).

Meanwhile, Suresh a criminal misunderstand Shankar as CID during their train journey. Suresh sends his men to follow Shankar and traps him to find Solaimalai. However, Shankar outwits his men and escape with Uma's car coincidentally. Suresh notice Uma's car, and order his man, Alangaaram to spy on Uma and Shankar, still thinking that Shankar is spy to apprehend Suresh illegal business. While escaping, both Uma and Shankar gets acquainted with Jaya.

Shankar soon finds that the car driven by Uma is belongs to Solaimalai. Shankar sends letter to his mother to find out more details about Solaimalai. Pasupathi advertise in a paper via Alangaaram (Suresh's man) for English music teacher. Shankar with the help of Karpagam and Jaya disguise as an old English music teacher to find out the real Solaimalai. Thirumangai a.k.a. Jaya helps Uma to return her lost necklace. While return the necklace, Thirumangai finds out her own baby photo and about it. Pasupathi and Uma reveals, it is Pasupathi first born daughter and Uma's sister. Without knowingly her own photo, Thirumangai a.k.a. Jaya vows to find Pasupathi's eldest daughter (herself). Suresh man kidnaps Karpagam, whom both earlier on, in train journey. Karpagam assist Suresh to capture Shankar. However, during fight (as disguised old English music teacher), Shankar manage to bash them. However, Uma recognize the disguise, but pretend not knowingly and falls for Shankar.

Eventually, Samundi manages to find Solaimalai house and threaten to kill him. Shankar who turns out to be there finds out the truth. Shankar fights with Samundi. Samundi manage to escape. Shankar got hurt in the fight, this is also watched by Alangaaram (Suresh man). Alangaaram brings Shankar to a fake doctor and give Shankar a sedate injection.

Soon Suresh (S. A. Ashokan), a notorious criminal imprisons Shankar, and impersonates him, for his wealth. Parvati is forced to play along, as Suresh threatens to kill Shankar. Thirumangai foster father(blind man) gets seriously ill reveals her true identity to Karpagam. Karpagam sends money to his friend to buy medicine. However, his friend was pick-pocketed by Thirumangai. Thirumangai repent for her deed. Uma reveals to Parvathi, that she loves Shankar. Parvati supports her decision, though Suresh black-mailing her. Karpagam manage to find Shankar and Parvati being kidnapped and blackmailed respectively, hatches a plan to rescue both of them with assistance of Thirumangai. Thirumangai manage to steal the entry token from Suresh and manage to rescue Shankar.

The movie ends, with Shankar and Uma united together and Pasupathi manage to find her eldest daughter Jaya. Jaya marries Karpagam, who is a CID.

The casting is established according to the original order of the credits of opening of the movie, except those not mentioned.

Thedi Vandha Mappillai is a tale of mistaken identity, with an innocent man, like the plot of Hitchcock's NORTH BY NORTHWEST.

This is the 4th and last collaboration between MGR and B. R. Panthulu (the boss of Padmini Pictures)

The album was released in 1970.

• Thedi Vandha Mappillai at IMDb