Po xiao shi fen (1968)

A young guard witnesses the corruption of the system during his first night call in the tribunal. A series of dramatic stories told by each prisoner to the judge ensues in flashbacks. The young guard has some doubt of conscience on his new job, but an elder guard who is also his uncle reassures him it's just a matter of time. The guard back home at dawn forgetting every injustice he witnessed because his wife has just given birth to a baby.