Sean Connery leads a secret society of Irish immigrant workers in violent protest against conditions in the Pennsylvanian coalmines of the 1870s. Hired to infiltrate their ranks, Richard Harris plays the detective whose loyalties become divided once he sees the exploitation for himself.
Based on real events, largely shot in the original locations and exquisitely photographed by James Wong Howe, Martin Ritt's sombre, elegiac saga was a box office bomb (failing to make enough to cover even Connery's fee domestically) but the two leads - ably assisted by Samantha Eggar and Frank Finlay - do a fine job with the humourless script.