An old man from Ghurghutia village near Palashi invited Feluda to solve a puzzle. The man's pet parrot recites a numeric code which is actually the combination number of his iron chest. The parrot says— Trinayan, o trinayan, ektu jiron. When Feluda solved the puzzle, he gave him four rare books of Émile Gaboriau as a reward. The very next day when Feluda returns to Kolkata with Topshe, something fishy smells in the old man's house. He started the last time investigation and it revealed that it was all a made-up plan and there was a murder behind the entire plot.
Feluda is called to Gosaipur by Jiban Mallick, the son of the local Zamindar Shyamlal Mallick to investigate a threat of his father's life. Everyone in the village knows that father and the son are at loggerheads. Shyamlal is also an eccentric who eschews anything modern. Then, instead of Syamlal, his son Jiban Mallick is killed and the wealth of Mallick's looted. Oddly though, the dead body of Jiban Mallick vanishes, only to reappear again. Feluda works this out with a mixture of investigating skills and deception.