The film opens to an expanse of countryside and paddy fields. A taxi trundles peacefully amid the scenery. Inside is a couple - a middle-aged man rested on the rear with his wife beside. As the car passes by a river in the village, a flicker comes over the man's features. It's the river of his childhood play, of his fond memories of home - an element of fascination that years of urban living can't quite obscure.

At home, the mother and elderly in the household are pleasantly surprised at the unexpected arrival of Unni and wife Thankamani. Their coming from Bombay this time is however, more than a ritual visit. Haunted by visions of violence and squalor, Unni has longed for the peace of home. The riots and violence in the city have wrought disquiet on his sensitive nature. A psychiatrist in the city advises a change of air for the couple.

'At first I thought he was only being fussy,' recalls Thankamani as she recounts Unni's uneasiness on coming home from office. ('... there's blood everywhere - in the streets, trains, in buses. Everywhere ... pools of blood'). Soon though Unni's attention to cleanliness turns obsessive.

'He'd wash the Rupee* notes on getting his salary, neatly laying them out to dry. He'd seal all doors from the inside; the little air vents too, afraid that the 'smell of gunpowder' might seep in from the outside. And then when he'd take to writing those long letters home.... then again he'd feel that 'words are impure' and clean his pen!'

Unni's mother and uncle reassure Thankamani as she expresses her apprehensions. It has come at a time when she's carrying and needs relaxation. An astrologer is called for to suggest a remedy. He concludes that Unni is under a 'lunar influence'. In its sinister hold, he's possessed of the spirits that dwell in water. He harkens to an earlier episode in the household. Great uncle Sankunni Nair had suffered similar delusions - and tragically met with a watery end on a moonlit night.

Shaken by the foretelling the family sets about religious rites to pacify the water souls. As the film unfolds, the parallels between myth and Unni's disposition become painfully apparent. On a fateful night of the full moon Thankamani wakes up to find Unni missing. The uncle gathers his men and they set out in a frantic search. But where to look? The well in the backyard holds no clues. They march to the river, torches held high against the beating wind.

But Unni is already far away; in a frenzied search for water in the drying river. He ventures farther and farther into the sands, unbounded in his seeking. And as a wind lashes from the thicket, the moon darkens at the brow. An age-old curse is revisited. Unni lurches into the waters and is choked to death.

As though on cue, Thankamani is jolted from her sleep. Coming in the open she senses a fatality in the night air. A sweeping wind crosses the threshold throwing leaves helter-skelter. The moonlight falls serenely on a picture of uneasy calm.