Light Through Glass is the fifteenth in Elizabeth Lemarchand's Pollard/Toye series. It's $0.99/£0.99 at Kindle US/UK. It's a Kindle Countdown deal good for about 5 more days - a bit less in the UK and a bit longer in the US.
Kindle US:
https://www.amazon.com/dp/B07R918YG3
Kindle UK:
https://www.amazon.co.uk/dp/B07R918YG3