Trial 4 is the story of Sean Ellis, accused of the brutal killing of Boston Detective John Mulligan in a Walgreens parking lot and imprisoned for more than 20 years as a result. The eight-episode Netflix series follows the well-established conventions of the genre set by hit shows such as Making a Murderer. There's the colorful crusading lawyer, the clues that don't add up, the enterprising local journalist, the teary significant other, the turgid atmospheric soundtrack, and finally the broader socio-political relevance.
The reason the genre is so popular and compelling, though, is because at the center of each story is a heartbreaking injustice. As presented in Trial 4, the evidence against then-19-year-old Ellis is astonishingly weak, while the racial animus and self-serving corruption in the Boston police department is appallingly pervasive. The series gets its name from the fact that Ellis is awaiting his fourth trial—after two mistrials and a wrongful conviction—for a murder committed in 1993. His story, and so many others like it, are vivid illustrations of the principle that justice delayed is justice denied.