Ryan focused on the titular Michael Ryan, a private detective with a stringent code of ethics and a background as a soldier, police officer, and social worker. Ryan's work doesn't focus on divorce and domestic problems, but on serious crimes that, for some reason, the victims are unwilling to take to the police. He is supported by his secretary Julie King (who often becomes involved in fieldwork), cab driver and later assistant Tony Angelini, and police liaison Detective Sergeant Dan Cullen.
According to Don Storey in Classic Australian Television,
Number in series: 23'The production standards of Ryan are very high -- good writing, solid acting performances, smooth direction and excellent camera and editing work combined to form a polished and professional product. And Ryan was very successful overseas -- proportional to the number of episodes made, Ryan has probably done better overseas than most other Crawford shows. Yet it was the first Crawford show not to do well locally'.