Ko is a 2011 Indian Tamil political thriller film directed by K. V. Anand starring Jeeva, Ajmal Ameer, newcomer Karthika Nair and Piaa Bajpai. The film was released on 22 April 2011 to mostly positive reviews.

Ashwin (Jeeva), a young, energetic photojournalist working for the private newspaper Dina Anjal, witnesses Naxalites robbing a local bank. He chases them and manages to click photos of the robbers. When he tries to escape, he is stopped by a young woman (Karthika Nair) who assumes he is the culprit and helps the robbers to take his camera. However, he is able to secure the memory card of the camera and to prove that he is a press photographer he shows the photos to the police, who identify everyone except the gang leader (whose face is covered by a mask). At his office, he meets Renuka ‘Renu’, the woman who earlier mistook him, who has newly joined as Article Editor. Saraswathi ‘Saro’ (Piaa Bajpai) also works in his office who has feelings for Ashwin. After finding out that Ashwin likes Renuka, she sacrfices her love.

Vasanthan Perumal (Ajmal Ameer), a recent graduate and engineer, strives hard to enter the political field. He is in contest against his rivals who capture the people at the time of elections by giving freebies and money. No one cares about Vasanthan and his team of graduates, who promise a healthy government to people. Their group name happens to be 'Siragugal'.

Meanwhile, Renuka writes a cover story about politician Aalavandhan (Kota Srinivasa Rao), describing his attempt to marry a minor. Enraged by this, Aalavandhan barges into the newspaper office and shouts at Renuka. The audio recording of her interview disappears, and she is fired from her job for falsified reporting. Ashwin now risks his life to capture the pictures of Aalavandhan who actually engages in child marriage. Later the story with the photos is printed in their newspaper and this makes Renuka to fall in love with him.

Vasanthan organizes a political campaign meeting. Ashwin receives a text message from Saro that states there is a bomb underneath the stage where Vasanthan and his political party is. Ashwin manages to save Vasanthan, while he finds Saro seriously injured and fighting for her life amidst the riot, eventually dies from her injuries.

Ashwin, through a video clip recorded by another photographer, finds out that Saro was intentionally killed by someone. He later notices a resemblance between the leader of the bank robbery and this unknown killer, concluding that it is the same person.

Vasanthan wins in the elections taking majority, gaining the title of Chief Minister and his party raises to the secretariat. He orders the release of 20 naxals on Republic Day, citing humanity. Hearing this, Ashwin rushes to meet Vasanthan. In Vasanthan's office, he finds the leader of the bank robbery who had also killed Saro. He tells Vasanthan about it, but he ignores him and pretends to be busy. Ashwin then follows the leader to his hideout.At the same time, the CM (Vasanthan) orders Tamil Nadu Police to go kill the naxals at the address Vasanthan gave and the Police Commandos surrounds the perimeter. There he learns that it was Vasanthan who, with the help of the naxals, planted the bomb and killed Saraswati as she saw the bomb being planted. In the end Vasanthan gets killed by a blast. Ashwin never reveals the relationship between Vasanthan and the killer to the media. Ashwin feared that if he does so, other party members who won along with Vasanth in election will lose their seats because of people. Ashwin tells the press that Vasanth sacrificed himself to kill the naxals.