Joe was a blind man from Tadcaster, England. He was a friend of the Third Doctor. His sightless knowledge of the seaside town was key to defeating the Master, who had enshrouded the town in an impenetrable mist. He guided the Doctor through Tadcaster until they found the source of the mist — the Master's collection of Sarkan mist-flowers. Joe physically attacked the Master and broke the special glasses which allowed the Master to see through the fog.
The Doctor appeared to have a long-standing friendship with Joe which predated the Master's incursion at Tadcaster. (COMIC: Fogbound)