Digging up the past is dirty business. Northern Irish indie The Dig, the first feature from brothers Andy and Ryan Tohill, brings viewers out to the bog, for a grubby, mucky, effective drama of guilt and redemption. Written by Stuart Drennan and assisted by NI Screen, the film stars Moe Dunford as Ronan Callahan, a convicted murderer with a memory problem who returns to his small Irish village and finds the father of his apparent victim (Lorcan Cranitch) on an obsessive quest to unearth his daughter’s body. Flagged by Emily Taafe as the victim’s sister, and Francis Magee as a menacing Sergeant, the repentant Ronan picks…