Frank attempts to save his team, and pays the price; at the same time, the wives get creative trying to make life on the Hill more interesting.

The loss of one of their own leaves the community reeling; and new security measures interfere with the work being performed by the scientists.

The arrival of a high-profile guest shakes things up. Frank is haunted by his past.

Helen and Charlie deal with a crisis; Abby embarks on a journey of self-discovery.

Both Charlie and Frank face serious questions as to the future of their projects.

An unexpected visitor arrives on the Hill.