Stingray (1964)

S1E8 An Echo of Danger

Phones doubts his capability to serve after X20's scheme to tarnish his reputation almost works. In a clever disguise as a psychiatrist, X20 undermines Phones' assertion that he genuinely heard the sound that diverted Stingray from their escort mission. Ultimately, it is Lt. Fisher who uncovers X20's hidden sounding device, which exonerates Phones and proves his innocence.