House of Hidden Wonders (the)

Zinnie and her sisters live in the murky tunnels beneath Edinburgh's Old Town. They keep out of the way of the authorities and remain undetected. Until, that is, rumours of a ghost bring unwanted visitors into the caverns they call home. Among them, a young Arthur Conan Doyle, keen to investigate, and MacDuff, the shady owner of Edinburgh's newest attraction, the House of Wonders.
Caught up in a world of intrigue and adventure, Zinnie seeks answers. But how can she discover what secrets lie in the House of Wonders while also protecting the sisters she holds so dear?