When Dan had to kill Jim Martin, his wife comes to town with her three boys expecting the youngest and fastest to kill Dan.  Johnny is the only law in town when they come in and he does his best to resolve the situation before Dan returns from some (convenient) out of town errand.  He's able to get through to the young gunfighter who really has no lust to kill.  When her youngest leave her thrall, Ma tries to get her oldest to stop him and Johnny has to shoot him.  In the end, Johnny almost feels sorry for her.