"San Quentin" presents a good view of what goes on behind the walls of state prisons, not so different from today, except for high tech gadgets that make escape more difficult.

Lieutenant Druggin (Barton MacLane) is relieved of his temporary position as yard captain, much to his dislike. When an army officer, Captain Steve Jameson (Pat O'Brien), accepts a two-year assignment to be his replacement, Druggin sets about to thwart Steve's changes, believing them to be too liberal.

Before arriving at his assignment, Steve spends a night in a club with his army buddies where he meets and falls in love with the singer, May Kennedy (Ann Sheridan), unaware that she has a criminal brother, Red Kennedy (Humphrey Bogart), bound for San Quentin following his capture at the club the same evening.

After meeting May's brother at San Quentin, Steve is determined to reform the young man without informing him that he knows and loves his sister. Red figures in on part of Steve's reform program, selecting those most likely to be rehabilitated for the fresh air road jobs, before based on seniority and good behavior alone. Steve convinces the prison board by explaining how many of the seasoned criminals take advantage of the old system to use the jobs outside the walls as means of escape. All goes awry when 'Sailor Boy' Hanson (Joe Sawyer) pulls strings with Druggin to get assigned with Red on the same work detail. Hanson needles Red about his sister being exploited by Steve by using her brother as a weapon. Hearing about Steve and May's relationship for the first time so angers Red that he throws in with Hanson and they make their getaway. It is now up to Steve to catch Red before he is totally lost to crime.

"San Quentin" has a stellar cast that raises this somewhat routine prison drama to higher ground. Humphrey Bogart's character runs the gamut of emotions but remains true to form as a wannabe tough guy with a chip on his shoulder. The gifted actress Ann Sheridan was seldom given an opportunity by the studio to strut her stuff, but she could make even the most thankless role shine. This time she is given an opportunity to show off her singing talent. Pat O'Brien, while not a versatile actor, could be counted on to give a good performance. The supporting cast of character actors makes every aspect of this tough prison drama believable.

Veteran director Lloyd Bacon delivers the goods in creating a fast paced film with an exciting chase scene near the end, filled with some daring stunt work, especially the motorcycle jump. There is exceptional camera work by Sidney Hickox of the environs of San Quentin, in particular the shots of the yard with the prisoners at times appearing almost surrealistic.