1x4 - Gunsmoke

When returning to Dodge, Chester and Matt are confronted by Holly Hawtree, whose father is desperately ill with gangrene. His only hope for survival is amputation of the affected leg. Matt performs the surgery, but the gangrene has spread too far and the old man dies. Matt later discovers that the presumed accident leading to Mr. Hawtree's condition was actually caused by Ben Walling, who has his sights on Holly.