ARCTIC WARGAME by Ethan Jones is free on Kindle from the 10th through the 12th. I read and reviewed it back in May and enjoyed it thoroughly. Justin Hall is a Canadian intelligence agent investigating an incursion onto Canadian soil in the north.
The author has a new novel in the series coming this fall, as well as a short story featuring Hall. Not to mention a short unrelated to the others. Those I bought and enjoyed as well. Here's the link.