Gunn’s Mission by Delilah Devlin

After surviving a catastrophic helicopter accident that left him scarred and unable to continue serving on the Teams, former Navy SEAL Gunnar “Gunn” Nielson is settling into life as a Brotherhood Protector in the Yellowstone, Montana, office.
When a request from the U.S. government arrives for a protection detail for someone with extensive cold-weather experience, Gunn, born and raised in Minnesota, is tapped for the job. He soon discovers that he will be the lone protector for a group of scientists working at a research facility on a floating island in the Arctic Ocean.
After discovering that one of her team members was murdered, Facility Chief Maddie Russo is grateful for Gunn’s expertise. Thinking the murder might have been committed by someone trying to interfere with a military-sponsored study, she and Gunn have to keep her team safe as the work continues.

Maddie and Gunn grow closer as the weather turns colder and the threats to the facility and its inhabitants continue.