Episode Summary:
Hoss's horse has fallen on him and Ben brings him to the nearest town only to find that the only doctor, Michael Johns (Kelley), is in jail awaiting execution for murder and not allowed to speak with anyone. Leaving Hoss with Mrs. Johns, Ben manages first to see Johns and then to persuade Judge Grant (who is eager for personal revenge on Johns) to allow Johns examine Hoss. Johns demands - and gets - a promise of $10,000 to be paid to his widow regardless of the outcome. That settled, Johns determines that Hoss has a punctured lung and requires an operation. While waiting, Ben gets the story of the murder charge from Johns' handyman Danny Culp. Danny saw Johns fighting with newspaper reporter Stevens; Stevens pulled a gun and was shot in a scuffle. Johns then took time to overturn a set of type and stuff a piece of paper into the stove before the law arrived. Deputy Hoff, who blames Johns for his crooked leg, took Johns to Judge Grant and said Johns had threatened Stevens the day before. Grant then tried and convicted Johns of first-degree murder. Danny notes that at the trial, Johns seemed not to be trying to help himself, and stuck to his story that the fight with Stevens was over an unpaid bill.
      Johns emerges, having done all he can do, and goes back to jail. Ben finds that the torn-up paper reports on a crime in Pennsylvania and demands that Johns explain why he is sacrificing himself. Eventually, Johns does: back in Coaltown, Karen had embezzled funds in order to meet her own medical bills for a lung ailment and to get Michael through medical school. Stevens had followed them west to blackmailing Johns If Karen goes to prison in Coaltown, she'll die; if she finds out what was going on she'll tell Grant herself. Johns begs Ben not to go to Grant. However, as they are tying Johns up at the gallows (tactfully built right outside the Doctor's house), Ben confronts Grant with abuse of his judicial power. He shows Grant the paper, spills the story, and insists that Grant also knows Johns did his best for Grant's wife. Grant goes out to signal the execution, but instead declares Johns innocent, and assures the happy couple that he will make sure they are not troubled further.

Notes:
This role is an excellent vehicle for Kelley - keeps one guessing what Johns is up to, and the revelation is nicely handled. But perhaps I like it so well because he plays Johns very much as he would later play McCoy - with a fine sardonic wit, a feisty temperament, a compassionate heart... and even that same instant transition from caustic defensiveness to reassuring competence when confronted with a patient.
For Trekkers:
This is the one where Kelley has the line, "I'm not a doctor, I'm a condemned murderer" - seen sometimes in composite clips shown at ST conventions.
Jonathan Hoyt (Judge Grant) played Dr. Piper in "The Cage"

Sources: viewing; Guyer 1991; Brooks & Marsh; Lentz (1997)