A pair of musicians are performing their act when one of them is almost electrocuted. Mannix is hired to look into the matter. But the detective faces twists almost immediately. For starters, the woman who hired Mannix isn't who she said she was. Mannix also needs to act fast before another attempt on the musician's life is made.
Joe Mannix receives an urgent phone call from his friend George Lassiter asking him to come to Albuquerque because of a problem with Lassiter's daughter Jeannie, who is also Joe's goddaughter. Mannix arrives quickly only to be told that the problem has been solved. Sensing that he's not receiving the whole story, though, Mannix decides to conduct his own investigation -- leading him to discover that his friend is involved in a novel form both of kidnapping and of paying the ransom.
Jenny Cole, the daughter of a friend of Joe Mannix, awakens after almost a year in a coma following a hit-and-run accident. But the celebration of her return to health is soon cut short when someone tries to kill Jenny. This leads Mannix to conclude that Jenny must have seen something on the day of the accident that she shouldn't have seen -- and that someone wants to tie up that loose end by "putting her to sleep" permanently.
Someone has been calling Joe Mannix with vague threats of harm, and he initially disregards them as an occupational hazard. But when the threats turn into a near-fatal attack, Mannix reviews his old cases for a clue to the person's identity - and thinks he may have found it in an old extortion case in which he sent the extortionist to prison.
After spending three weeks incommunicado on a fishing trip, Mannix returns to Los Angeles to learn that his buddy from the Korean War, Harry Endicott, has apparently been killed in a plane crash. Finding a letter from Endicott appealing for help that was mailed the day before the crash, Mannix decides to run down some leads in Endicott's hometown of San Francisco. But upon his arrival, Mannix finds the mystery much deeper than he suspected - when first several people claim to have seen Mannix in the past few days, and then he locates an apartment where everything ...
Joe Mannix is visited by Japanese detective Tami Okada (whose first name is pronounced as if spelled "Tommy"). Searching for a missing Japanese government courier who was apparently kidnapped upon arrival in Los Angeles, Okada asks Mannix for help. Mannix agrees, escorting Okada to the Japanese Village in Buena Park, and to "Little Tokyo" -- but their investigation soon leads to suspicions that the courier's disappearance may have been staged.