At the beginning of the episode, Mark is feeling a little grown-up and actually talks back to his Pa while feeling bad for his mother dying and leaving him. While the two, Lucas and Mark, set off to buy a bull they camp by some strangers. During the evening, Lucas kind of embarrasses Mark while he listens to a passing woman singing. Right before going to bed Lucas tells Mark not to drink the water from the passing travelers because it might be polluted. However, Mark is too busy feel sad for himself and does not heed the advise of his father. During the night Mark gets up and takes a drink from the barrel of water that belong to the travelers.
A few days later at the ranch, Mark begins to run a fever and before long, due to the high fever, Mark begins hallucinating. With Doc Burgess out of town they have to send for a neighboring doctor, Henniken. He finds out that Mark has typhoid fever- a disease that often means death. It going to be touch-and-go as Mark's fever makes him have delusions about things that even includes his dead mother.
This is a classic 'Rifleman' show where Lucas has to be strict with Mark for his own good. But it still does not lessen the love the man has for his son even when Mark disobeys his words. Even with a dream scene being too covert, it still made for a nice and entertaining show.