Karuthamma Sheela is the daughter of an ambitious fisherman, Chembankunju Paravoor Bharathan. She falls in love with Pareekutty Madhu, a young fish trader, and together they share a quiet, hopeful dream. Chembankunju’s sole aim in life is to own a boat and nets, a goal that could change the family’s fortunes. Pareekutty steps in to help finance this dream, but with a clear, hard condition: the day’s catch must be sold only to him. The arrangement, born from necessity and ambition, plants the first seeds of tension in the small fishing world they inhabit. Chakki Adoor Bhavani, Karuthamma’s mother, catches wind of the affair and pleads with her daughter to stay within the rigid, traditional boundaries that govern their community. The lingering belief among the fisherfolk is that a fisherwoman’s life must be squarely within those lines, a belief that puts Karuthamma at odds with her own desires.
Karuthamma Sheela makes the painful choice to honor duty over love, sacrificing Pareekutty to marry Palani Sathyan, an orphan Chembankunju found during one of his fishing expeditions. Karuthamma accompanies her new husband to his village, even as her mother falls ill and her father pleads for her to stay. In a harsher moment, Chembankunju disowns her, marking a turn in the family’s fortunes. With time, Chembankunju’s ambition grows bolder—he acquires more boats and nets, and his increasing wealth fuels a growing heartlessness. His greed and crooked deals push Pareekutty toward bankruptcy, reshaping the once-close bonds between them.
After the death of his wife, Chembankunju marries Pappikunju Philomina, the widow of a man from whom he had bought his first boat. This new union stirs tension within the family, particularly as Panchami, Chembankunju’s younger daughter, grows to hate her stepmother and to taunt both her and her new stepson. Pappikunju’s son, barely able to endure the daily humiliations, begins to seek a better life elsewhere. In a desperate move, Pappikunju steals money from Chembankunju’s savings to help her son, a betrayal that Panchami uncovers and reports. Chembankunju ousts Pappikunju from the home and gradually slides into madness, a collapse that unsettles the entire household. Alarmed by her father’s deterioration, Panchami leaves her home to join Karuthamma.
Meanwhile, Karuthamma has striven to be a good wife and mother, but the village is consumed by gossip about her past with Pareekutty. Palani’s friends ostracize him and refuse to take him fishing, and Palani begins to fish on his own in a single-person boat. Karuthamma supports him as they begin to prosper and eventually become parents to a daughter. At first Palani trusts his wife, yet the poisonous talk around them sows doubt in his heart. The moment arrives when he overhears Karuthamma asking Panchami about Pareekutty and confronts her, accusing her of infidelity and leaving to go on his fishing expedition alone.
In a cruel twist of fate, Karuthamma and Pareekutty cross paths again that night, and their old love is stirred anew. Palani, meanwhile, is at sea, baiting a shark, when he is swallowed by a powerful whirlpool. By morning, Karuthamma and Pareekutty are found dead, hand in hand, washed ashore. Off in the distance lies the lifeless body of the shark that Palani had baited, a stark reminder of how the sea and its moods shape every life around them.
