Blind Lake

From back cover of Tor paperback July 2004:

At Blind Lake, a federal installation in northern Minnesota, scientists are spying on everyday life on an alien planet, using a technology they barely understand. No interaction with the aliens is possible. All the scientists can do is watch.

Then, without warning, a military cordon is imposed on Blind Lake. All communications with the outside world is cut off. Vital supplies are delivered by remote control. No one knows why.

Among the scientists are Nerissa Iverson and the man she recently divorced, Raymond Scutter. Despite everything, they continue to work together. Ray believes their efforts are doomed. But Nerissa has come to believe that the particular alien she has been monitoring has an elusive logic to its behavior -- and, moreover, that the alien is somehow aware of being observed.

But time is running out. Ray is turning hostile, stalking Nerissa. The military cordon is tightening. Understanding had better come soon...