Vanjaram (Mime Gopi), a gangster, owns an asian arowana fish named Kattappa, which is believed to be his lucky charm. One night, Kattappa gets stolen by a thief, and after a string of events, it ends up in Pandian's (Sibi Sathyaraj) house. Pandian is considered an epitome of bad luck after multiple business failures, and his father even calls him "Bad Luck" Pandian. Pandian falls in love with and marries an open-minded girl named Meena (Aishwarya Rajesh). They move into a new apartment, where they meet a little girl named Kayal (Baby Monica) who has lost her mother at a young age and develops a bonding with the couple. Kayal yearns for a miracle which will make her wishes come true. When Kattappa ends up in their house, they discover that it is indeed a lucky fish.