A Deadly Waltz (Victorian Gothic Mysteries) by Sophia Queen

Next, she unpacked her chemicals, lab equipment and agency correspondence materials. She pushed these materials against the far wall beneath her bed and placed her emptied travel bags in front of them. Not the most secured hiding place, but it was the best she could do at the moment.

A Deadly Waltz by Sophia Queen

Karina Rouelle joins an all-female investigative agency. For her first assignment she poses as a governess  and goes to Westford castle. The Countess of Westford had died mysteriously and Lord Sebastien Blackwell is the top suspect for the death of his wife. Now Karina too is on a run from an arranged marriage to a deranged man. She does not wish to be found by her greedy uncle. 

With secret passages and unknown sounds, the castle has too many secrets. Even the investigative agency has a secret head. Karina is right in the midst of it all. Things get worse when Sebastien asks her to be his escort to escape the hordes of female admirers. Karina is attracted to cursed, dark lord. 

With twists, turns and the gothic element, this is more of a suspense than a romance. Karina comes out to be a very strong personality. She has the right knowledge of science to experiment with chemicals, and also can wield a knife or a gun. She is not afraid of secret passages, chambers or the sounds. She goes right in it to investigate. 

The secondary characters too are well drawn and the mystery element is held right to the end.