Nick Carter, consumado artista del disfraz y detective que aparte de sus condiciones físicas ya utilizaba el método deductivo para solucionar los casos criminales, se traslada a Praga, donde investiga la misteriosa desaparición de un perro propiedad de una duquesa. El perro no ha sido sino una víctima para probar la capacidad de Adela, la nueva arma secreta de «El Botánico», viejo enemigo de Nick Carter.
It is 1905. The police director gets Jindrich Legenda (Eduard Cupák) shadowed as, yet Legenda had served his sentence for a burglary, the jewels have not been found. Russian revolution encouraged also Czech workers to fight for their rights. Radical anarchists are followed by Legenda's friend Karel Wohryzek (Vladimír Mensík) who was forced to collaborate with the police as he was convicted of pornography distribution.