Athadu (transl. He) is a 2005 Indian Telugu-language action thriller film written and directed by Trivikram Srinivas and produced by Jayabheri Arts. The film stars Mahesh Babu, alongside Trisha, Sonu Sood, Prakash Raj, Nassar, Sunil, Sayaji Shinde, Kota Srinivasa Rao and Brahmanandam. The music was composed by Mani Sharma, while K. V. Guhan handled the cinematography. The film follows a professional killer hired to stage the assassination of a politician, only to be framed for the actual murder, forcing him to assume a new identity while evading the law.

Athadu was released on 10 August 2005 and received positive reviews from critics and audiences, emerging as one of the highest-grossing Telugu films of the year. It won three Nandi Awards and a Filmfare Award South for Best Director – Telugu. Over time, the film gained recognition as a modern classic in Telugu cinema and holds the record for being the most telecasted Telugu film, having aired over 1,000 times on television. The film was remade in Hindi as Ek: The Power of One (2009) and in Bengali as Wanted (2010).

Nandu (Mahesh Babu) is a skilled (assassin-for-hire). Along with his partner Malli (Sonu Sood), he is hired for ₹1.50 crore by politician Siva Reddy (Sayaji Shinde) to stage an assassination attempt on him, intending to gain sympathy votes. However, on the day of the staged attack, Siva Reddy is actually shot dead, and Nandu is framed for the murder. During his escape, Malli dies in a car accident. Nandu manages to evade the police by jumping onto a moving train.

On the train, Nandu meets Parthasaradhi "Pardhu" (Rajiv Kanakala), who is returning to his hometown, Basarlapudi, after running away as a child two decades earlier. While the train halts at a station, the police searching for Nandu arrive. A sub-inspector, mistaking Pardhu for Nandu, shoots and kills him.

Nandu, intending to inform Pardhu's family of his death, arrives in Basarlapudi. However, Pardhu's unsuspecting family mistakes Nandu for their long-lost relative and welcomes him with open arms. Over time, he bonds with them and falls in love with Poori (Trisha), Pardhu's cousin. Nandu helps the family resolve several issues, including protecting their farmland, aiding a struggling family affected by Pardhu's past actions, and withdrawing money from Pardhu's bank account to fund a relative's wedding. He confides his real identity to Pardhu's childhood friend Ramana (Sunil).

Meanwhile, CBI officer Anjaneya Prasad Sharma (Prakash Raj) is assigned to investigate Siva Reddy's assassination. Noting inconsistencies in the evidence, he tracks leads to Basarlapudi but fails to uncover Nandu's identity. Eventually, he discovers a withdrawal from Pardhu's account, calls the household, and tricks Nandu into revealing himself. Realizing the trap, Nandu escapes.

Prasad informs Pardhu's family of his real fate and departs. The revelation leaves them devastated, but Ramana defends Nandu, highlighting his contributions to the family. Nandu returns and admits he initially intended to inform them of Pardhu's death but refrained upon seeing their happiness at his arrival.

Pardhu's grandfather, Satya Narayana Murthy (Nassar), privately acknowledges Nandu as his grandson, noting that his actions have proven his place in the family. He hands Nandu a shotgun, once owned by Pardhu's father, which had misfired due to an obstructed barrel, and encourages him to uncover the truth and clear his name.

Nandu contacts Baaji Reddy (Kota Srinivasa Rao), Siva Reddy's associate, and blackmails him with a fake recording into confessing. Baaji Reddy reveals that Malli is alive and was bribed to assassinate Siva Reddy and frame Nandu so that Baaji Reddy could secure the chief minister position. Nandu secretly records this confession.

Nandu tracks Malli to a church, where they are ambushed by Baaji Reddy's corrupt officers. Nandu eliminates the attackers and confronts Malli, who takes Nandu's shotgun and aims at him. However, when he fires, the obstructed barrel causes the gun to backfire, killing him. Prasad arrives, and Nandu hands over the recording. Prasad confronts Baaji Reddy, who arrogantly dismisses the evidence as inadmissible in court. However, Prasad points out that Siva Reddy's vengeful son would not hesitate to kill him once the truth emerged. With no escape, Baaji Reddy commits suicide.

Later, Prasad finds Nandu performing Pardhu's last rites. Addressing him as Pardhu, he reveals that he has officially cleared his name and allows him to go free. Nandu, having fully embraced his new identity, returns to Basarlapudi to live with his newfound family.