Feluda, Topshe and Topshe's father visit Darjeeling as tourists for a few days. There, Feluda and Topshe meet Rajen Majumdar, who was an established lawyer based out of Kolkata, but after retirement had settled in Darjeeling. After retirement, Rajen-babu has developed an interest in antiques, and has built quite a formidable collection in a span of a few months.
Rajen-babu has been threatened by a letter posted to him, which mentions that he will be punished soon for misdeeds of his past. Rajen-babu panics and agrees to have Feluda investigate the matter.
Feluda and Topshe also meet Tinkori Mukhopadhyay, who is staying at Rajen-babu's house as a paying guest for a few days and Abani Ghoshal, an antique property dealer. Tinkori-babu is a renowned writer of Bengali detective fiction, and he writes fiction under the name Guptochor (i.e. spy). Feluda mentions that Tinkori-babu is one of his favourite writers of detective stories in Bengali. Abanimohan Ghoshal visits them while Feluda and Rajen-babu are talking. He is interested in buying a bell, supposed to have come out of the household of the Dalai Lama, that is in Rajen-babu's possession.
Amongst other things, Feluda notices that the letter that was mailed to Rajen-babu is created out of words cut out from a newspaper. Tinkori Mukhopadhyay helps Feluda in his investigation, by suggesting that the cuttings are from Anandabazar Patrika, recognizing the unique font used in that newspaper.
Feluda visits to Dr. Phoni Mitter, Rajen-babu's physician, and comes with a theory that the doctor might have sent the letter in order to inspire fear in Rajen-babu and make him ill in order to get into business.
Later, Feluda spots Prabir Majumdar, Rajen Majumdar's estranged son. He was thrown out of the house by Rajen-babu for trying to steal money, and Feluda finds it curious that he is in Darjeeling, and obtains his address. When Feluda meets Tinkori-babu, he tells him about seeing Prabeer Majumdar, and they both agree that it is a very curious thing.
A second incident happens a following night. A man wearing a ghostly mask had entered Rajen-babu's room at night. Rajen-babu is extremely scared and agrees to Feluda and Topshe staying the night over at their place the next day. They drop off Tinkori-babu at the station.
Feluda starts a rigorous process of elimination. He manages to confirm that the doctor had been visiting a patient the previous night, and discovers that Prabeer Majumdar, having made quite some money at the local races, has little to gain from threatening his father. He meets another collector of curios, Mr. Gilmour, and discovers that the bell with Rajen-babu is a fake. Abanimohan Ghoshal is aware of this, and also knows Prabeer Majumdar. However, since they were at a party which continued until late at night, both of them can be ruled out from being the intruder.
Feluda then sets about checking the masks in Rajen-babu's room. He tries them on and discovers a faint smell of cheroot. The only person in the vicinity who smoked cheroot is Tinkori-babu. Tinkori-babu, though, had left for Kolkata a day ago.
It is later confirmed that it is indeed Tinkori-babu who is the real culprit. Tinkori-babu has left a letter to Rajen-babu, referring to him as Raju, apparently Rajen-babu's nickname. Tinkori-babu was Rajen-babu's classmate in Bankura Missionary school, and was unlawfully, and seriously injured by Rajen-babu during a 100-yard race at the school's annual sports festival. Since Rajen-babu had left Bankura after the incident, Tinkori-babu never got a chance to avenge the incident then. After arriving at Darjeeling, Tinkori-babu could identify his old adversary from school from an old photograph, and decided to avenge that old incident by putting Rajen-babu under some discomfort. Thus, he sent the threatening letter, and also scared Rajen-babu at midnight in Rajen-babu's bedroom wearing the mask.
In this story, Feluda's age is 27, and Topshe's is exactly half of Feluda's i.e. 13 and a half.
This is the first of two novels of Feluda, that are set in Darjeeling. The other is Darjeeling Jomjomaat.
Sandip Ray mentions Darjeeling as one of the favourite locations of his father, and thus Satyajit Ray's first movie made from original written screenplay, Kanchenjungha, as well as the first Feluda novel was based out of Darjeeling.
In the first few Feluda stories, Topshe is mentioned as Feluda's maternal cousin. Later, he is confirmed as Feluda's paternal cousin. Thus, in the first few stories (including Feludar Goendagiri), Topshe's full name is Tapesh Ranjan Bose. It changes to Tapesh Ranjan Mitter later .
1. Sandesh, (serialised) December 1965, January–February 1966.
2. Ek Dojon Goppo, part of a collection of 12 stories, June 1970, Ananda Publishers
3. Paharey Feluda, anthology, January 1996, Ananda Publishers
4. Feluda Somogro, anthology, January 2005, Ananda Publishers, ISBN 81-7756-480-3