Currently re-reading all the Sherlock Holmes stories, which I've always enjoyed,
If you liked Arthur Conan Doyle's Sherlock Holmes stories, you might like Andy Lane's Young Sherlock Holmes Series..
He writes with the permission of the Arthur Conan Doyle family heirs in a similar style;;
This is one book out of a series of three (I think?) I have read...
Summary:
Sherlock Holmes is sent to live with his unknown aunt and uncle in Holmes Manor in Hampshire over his school holidays when his father is unexpectedly sent overseas with the British Army. He cannot go home as his mother is unwell, and cannot go to London as his older brother Mycroft is busy working for the government. Wandering around the estate and the surrounding countryside he soon befriends a boy his own age named Matty Arnatt (who has witnessed an unusual death involving a cloud of death).
After a few days of holidays Sherlock discovers that his brother Mycroft has hired him an unusual American tutor named Amyus Crowe. During their first lesson together Sherlock finds a dead body on the Holmes' estate and witnesses the same death cloud surrounding the body that Matty had previously seen. He detects a yellow powery substance around the body and takes a sample of it.
With Matty's help he tracks down a warehouse which has links to one of the deceased, and almost dies in the warehouse when the villains set it alight. Holmes escapes the building, and determines that he must travel to Guildford and locate an expert in exotic diseases who might help identify the yellow substance. He, therefore, sets out with Matty on his barge to Guildford, and although they are attacked along the way by the villains, they nevertheless make it to his destination and discovers that the yellow substance is bee pollen. On returning home he visits his tutor's home, where he meets Crowe's daughter Virginia.
A few days later Sherlock is lured to a fair, where he is forced to participate in a boxing match, from which he is kidnapped and interrogated by the unseen Baron Maupertuis until he is rescued by Matty, and the pair go to his tutor's home. Knowing that the Baron has left his headquarters, Sherlock, Matty, Crowe and Virgina determine to follow and locate the Baron.
They discover that the Baron is shipping a weapon from a London wharf, and after a series of chases, Sherlock and Virgina are kidnapped to France by the Baron, and further interrogated. The pair escape and meet up with Crowe and Matty and set out to stop the Baron from trying to destroy the British Empire