Ironside's Aunt Victoria suspects foul play when one of her card-playing friends vanishes. Despite her nephew's admonitions, Victoria and her bridge partners shadow their missing friend's husband, who insists his wife left him.
With his assistants away, the chief receives a phone call telling him to expect a deadly visitor within sixty minutes. Ironside spends the remaining time improvising self defense without weapons - and trying to identify the caller.
Mark finally graduates from law school. He takes an interest in a janitor from the school who finds himself in jail accused of grand theft. Meanwhile Ironside struggles with the reality that Mark may eventually leave for his new career.
A hit man is given the job of killing Ironside before he can testify before the Grand Jury, and the hit man has well-deserved the reputation of never missing his mark.
Mark passes the Bar and takes on his first case. Unfortunately, Mark's defense of his client may impinge on Ironside's investigation of a hood's extortion racket. Meanwhile Mark and Diana decide to get married.
When a rising folk-singer's body is found in the water under the Golden Gate Bridge, suicide is suspected, but Ironside has reasons to suspect something else.
Ironside knows a man Mark ran errands for as a child is a convicted robber who may be involved in the murder of a gangland racketeer. Mark, however, defies a warning to stay away from his old acquaintance.
After a parole officer is shot at, Ironside finds the list of possible suspects is quite long. A drug pusher may be responsible since he is especially hard on them after his sister was confined to an institution after a bad drug experience.