Tokyo is in terror of a black figure, who merges into the night and is seen only when he shows the white teeth of his mocking smile. The strange figure's appearances come close to the house of a wealthy Japanese family, and wake in the memory of the father an association with a jewel that he once bought. The jewel had seemed a bargain at the time; but he later learnt that it had been stolen from an idol in an Indian village, and two Indians were said to pursue the stone relentlessly, taking the life of the owner's daughter, just as an Indian girl of the village had lost her life at the time of the theft.
The mystery runs along similar lines to Twenty Faces. Akechi is again away on business and Kobayashi steps in for him. This time the villains seem a bit more ruthless than Twenty Faces, who did not care for killing.
Straining his eyes he looked up at the ceiling. It was hard to make out; but it seemed that a small hole was opening there and through that something like a thick pipe was being pushed inside. Its diameter was about twenty centimetres.
Hey, what's this you're playing at? What on earth is that? Kobayashi braced himself, prepared for whatever might come, and kept his eyes fixed in that direction. As he did so, he thought he heard a "ga, ga ga" sound. And in that moment, suddenly, out of the mouth of the thick pipe, something white and foaming started to pour down like a waterfall. It was water. Water.
Oh, readers, what must our Kobayashi's surprise be at this moment?
The novel follows very much the pattern of the first book and has similar virtues. The villain is hilariously irritating, crowing like a child in his victories and mocking his opponents. The narrator moves between different viewpoints and attitudes, often addressing the readers and inviting them to speculate about what is going on, sometimes pulling the camera back and seeing events through the eyes of the people of Tokyo. The passage of time has perhaps given the story more interest, for the glimpse of Japan in the thirties that it offers. That includes such suprisingly modern items as burglar alarms with infrared sensors and helicopters. It also shares the fault, if you care, that all the surprises are much too obvious. An adult reader will work out almost everything that is going on immediately; and probably children are expected to spot most of it for themselves before the revelation.
The boy detectives club, which had a small role in the first book, is the title character this time; but its role is only slightly larger, and almost restricted to the first part of the book.
According to the Japan Foundation's translation database, there is an English translation by Gavin Frew, The Boy Detectives Club (Kodansha International, 1988).