Cobra is the short form of Co-brothers (Kottayam Brothers). As the name suggests it tells the story of two brothers Raja (Mammootty) and Kari (Lal).Gopalan (Saleemkumar) and Balan(Manian Pilla Raju) play the roles of their security. Cobra lives only in places that start with Co. After Connaught Place, New Delhi, they shift to Kothamangalam. They are looking for brides for them with only one condition that they should be sisters. They find an alliance at Kothamangalam and their marriage gets fixed. But on the day of marriage, one of the brides gets late for marriage. Thinking that she eloped, Raja creates a fuzz there and the marriage gets cancelled. To escape from humiliation, they shift to Coimbatore. At Coimbatore, they meets Samuel (Lalu Alex) who is looking for prospective buyers for his house. He needs money for the education of his daughters, both of which are doing medical studies else where. While Cobras are negotiating the deal, they see the picture of the two girls(Daughters of Samuel) Sherly (Padmapriya) and Aany (Kaniha) and plans a marriage with them. Samuel wants to hide the news of selling his house from his daughters. So he asks Cobras to hide this news for another 6 months until their studies are over. Cobras say that they will do registration only after 6 months and during that period they will stay at Samuel's house as tenants. Meanwhile, Isaac (Babu Antony) and his brother is trying to forcefully take Samuel's house and his hospital. Isaac tries to humiliate Cobras on the day of inauguration of his new physical fitness center. Samuel and Isaac gets into a verbal fight and fixes a boxing match the next weekend with a deal that whoever wins the match will get the hospital. Isaac finds out that Raja has a twin brother named Shivadas who looks exactly like him. Isaac blackmails Raja saying that if he does not withdraw from the match, he will bring his twin brother to Kari. Raja thinks that it will break Kari's heart and so he decides to back out from the fight. But Kari and Samuel decides to carry on with the match. For the match, Raja joins them. Even during the match Isaac tries to blackmail Raja showing him Shivadas standing at a distance view from the venue. Initially Raja does not fight back and gets badly beaten. Then Kari comes to the ring and he gets badly beaten too. Seeing Kari getting beaten up, Raja decides to fight back and defeats Isaac and his brother. Meanwhile, seeing the love between Raja and Kari, Shivadas leaves the scene without anyone noticing.
