An explosion on the Liberty Oil pipeline in Backstrom's childhood home of Cooch County leads his estranged father, Sheriff Blue Backstrom (guest star Robert Forster), to Portland. Father and son, along with the Special Crimes Unit (S.C.U.), race to find the suspected eco-terrorist, before he/she strikes again. Meanwhile, Backstrom must confront old demons when dealing with his revered father, and romances are stirred when ex-fiancee Amy (guest star Sarah Chalke) pays Backstrom a late-night visit.