A man discovers a photo from 1982 that confirms his brother-in-law was not where he said he was when his wife (the man's sister-in-law) was murdered, prompting the man to call people in an attempt to solve a 35-year-old murder mystery.

The only thing special on this particular Monday for retiree, James "Jimmy" Furuta, is that he intends to organize the family photos of the past 30 years into neatly categorized albums. But when he uncovers a dated Polaroid shot back in 1982 of a car he once owned, his world is turned upside down. For he had sold that care to his brother-in-law and it proves he was not where he said he had been on the night before he found his wife, Jimmy's sister-in-law, murdered when he returned from a fishing trip. To get to the bottom of this mystery he begins to make phone calls to people associated with that tragedy and by day's end he will find the killer of a cold case that had been unsolved for 35 years. A story driven primarily by the phone call conversations of our hero to other characters appearing only in voiceover dialogue, "The Landline Detective" is an action packed murder mystery featuring only one on-screen character.