Longing for a quiet life in Ireland, and a reunion with Moya McCoy, Kevin and Brett instead journey eastward in an attempt to help Moab and his tribe battle their weird ursine enemy.

En route, they encounter an old friend of Kevin’s, Dr. Claustus. Hearing of Moab and Kevin’s plan against the bears, the old scientist has a couple of solid suggestions. As far as dealing with the bear’s mysterious mistress, Dr. Claustus’ advice is less concrete, but rather witty.

Meanwhile, the situation worsens dramatically for Moab’s tribe — he and Kevin are too late to save another victim from the fearsome Cave Bears.