Darkness by Karen Robards

Résumé:
Beautiful, brilliant Dr Gina Solomon is one of a handful of scientists stationed on a remote island off the Arctic Circle. Out conducting research in the last days before winter wraps the area in months-long darkness, she witnesses a plane crash over the Bering Sea, and rescues a survivor from the wreckage - Mal Connolly.
With a snowstorm stranding them unexpectedly, it's at least twenty-four hours before they return to the research station... and discover that all of the other scientists have been murdered.
Whoever killed them is still on the island, hunting Mal, a military weapons expert with a terrible secret. They'll do anything to stop him revealing what he knows. And now Gina is in danger too.
With no escape until the plane comes for them the following week, Gina and Mal try to stay one step ahead of the killers, and discover a potent sexual chemistry... But will they get off the island before they are swallowed up in darkness forever?