The Streets of San Francisco S4E18: Underground

🔍 **EPISODE ESSENTIALS**
**Title**: Underground
**Season/Episode**: S04E18
**Original Air Date**: January 29, 1976
🎬 **PLOT SUMMARY** (IMDb Verified):
When the brother of a cop is killed along with the mobster he was working for, the young officer is assigned to work undercover as a bookie to find out who ordered the hit. Stone, ordered to tell no one else about the man's assignment, is concerned that the officer is too concerned with revenge to handle the job effectively.
⭐ **CAST HIGHLIGHTS**
- Karl Malden as Det. Mike Stone
- Michael Douglas as Insp. Steve Keller
- **Guest Stars**: Robert Drivas, Claudia Jennings (Thumbnail Visible)
🌉 **EPISODE HIGHLIGHTS**
- Undercover bookie operation
- Cop's brother's mob-related murder
- Revenge vs. professional duty conflict
- Stone's secrecy about assignment
- Infiltration of gambling network