Tomorrow, When I Die — Karen J. Carlisle

Viola is a widowed optician with a penchant for detectiving. This Victorian Mystery series is set in a steampunk fantasy world and has a gaslamp flavour.

A life is in danger. Is it part of another plot by the mysterious Men in Grey? Viola must find out the truth before it is too late. A knock on the door could change everything.
It's all just a matter of time.