A summary of Lev Brusilov’s "The Trail of the Mechanical Monkey"

"The Trail of the Mechanical Monkey" is a detective novel by Lev Brusilov, published in 2024 by Eksmo. The action takes place in May 1893 in the provincial town of Tatayar: a provincial detective investigates mysterious nighttime occurrences, which are later traced to a wind-up mechanical toy, followed by a series of murders in a merchant’s house. The book is written in the tradition of classic Russian detective fiction, with elements of mysticism and everyday prose from the late 19th century.

The appearance of the monkey

The industrialist Savva Afinogenovich Protasov personally visits the head of the provincial detective police, Baron Foma Fomich von Spinne. This in itself is unusual: people like Protasov don’t work for detectives. The manufacturer explains that he bought an expensive, life-sized wind-up monkey from the "Children’s Joys" company in Berlin — a gift for his ten-year-old grandson, Misha. However, the toy nearly strangled the boy the first time it was wound up, after which it was locked in a closet.

That’s when things started to get weird. The monkey began appearing at night in the hallways and rooms of the house, even though the only key to the mechanism was under Protasov’s pillow. One night, the toy entered his bedroom and said, "Savva Protasov, hello!" — no longer addressing his grandson, as the German design suggested, but the manufacturer himself. In the morning, the lock on the closet was broken, and the monkey frightened his grandson Misha again.

Fourteen suspects

Von Spinne agrees to take the case privately: he works for the detective agency during the day and lives as a guest in Protasov’s house at night. At the very first dinner, the colonel announces to everyone gathered that a telegram had been sent to the "Children’s Joys" firm in Berlin. The reply confirmed that the toy had come with not one, but three keys. Two of them — in a blue linen bag on the monkey’s right paw — had disappeared without a trace. This means that one of the fourteen residents of the house possesses a key and is deliberately winding the mechanism.

Protasov describes his large family: his wife, Arina Ignatyevna; four sons — the practical but weak-willed Nikolai and his wife, Ekaterina; the obstinate Nikita, who dreams of St. Petersburg for the sake of a certain Glasha Kirsanova; the artist Andros, who has long been begging to go to school; and the quiet schoolboy Sergei; two daughters — the pious Agrippina and the plain, according to her father, Glafira; three hangers-on — Marya Potapovna, Pelageya Semyonovna, and the young Rufina Yakovlevna; and finally, the decrepit Uncle Evsey, a cousin of Protasov’s late mother. All of them are potential suspects.

The first conversations and the escalation of the conflict

At dinner, it becomes apparent that Arina Ignatyevna is extremely sensitive to the presence of a police officer. Her eldest son, Nikolai, becomes indignant when the conversation turns to a possible duplicate key, directly hinting that only his father could have kept the monkey. In the midst of the feast, old man Evsey intervenes in the squabble and publicly announces that the monkey had also come to his room, and that he is convinced Savva Afinogenovich himself has the key.

Von Spinne speaks separately with Sergei, the youngest of his sons. The schoolboy is genuinely frightened, but offers nothing of substance — he merely recounts his father’s story word for word. During an inspection of the playroom, the colonel discovers that the door is locked, though it has no keyhole — meaning it’s being deliberately held open from the outside. When Sergei finally produces the key, it turns out that the monkey itself is standing behind the door, already wound up and marching in place.

Murders

The situation changes dramatically when bodies are discovered in the house. Uncle Yevsey is the first to die — strangled. Then the detective agent von Spinne had secretly assigned to the house is killed. The method of murder is the same in both cases — a rope. Police doctor Vikentyev, after examining the bodies, concludes that both murders were most likely committed by the same person. But Protasov Sr. dies differently: according to the doctor, the injuries to his neck are consistent with a monkey’s mechanism. Savva Afinogenovich was killed by a toy.

The complicated story surrounding Rufina Yakovlevna’s hanger-on comes to light. She was simultaneously involved with the groom Leonty and with Yevno Abramovich Novoaronovsky, a man the elder Protasov had taken with him to Europe. Leonty, upon learning of the affair, strangled Novoaronovsky in the stables. Nikolai and Nikita both knew about it but kept silent: the groom had been in the household for a long time.

Interrogations and denouement

Von Spinne interrogates Protasov’s sons one by one. Andros is behaving erratically — frightened out of his mind. Nikolai and Nikita give confused, clearly prearranged testimony. When the colonel asks them to demonstrate how the groom strangled Novoaronovsky, both reproduce the same movements — a clear sign of collusion.

The investigation establishes that the keys to the mechanism were deliberately hidden by someone in the household, who used the monkey first as a scare tactic, and ultimately as a murder weapon, setting the toy on the manufacturer himself. The mechanical monkey, purchased in Berlin for a child’s joy, became the instrument of a calculated crime within the family, where everyone had their own scores to settle with Savva Afinogenovich.