“I’m going to tell you a story. But I’ll be honest. It doesn’t have a happy ending.”

That’s the first line of narration from the season premiere of Netflix’s “Narcos: Mexico,” which dropped today. The “Narcos” franchise, now in its fourth season, has never been about endings. It has always asked that its viewers come along for the ride, even while the basic plot details are well-known. After all, it is based on historical events, complete with regular splicings of television news clips.

This time, we’re in Mexico — specifically, it’s Guadalajara in 1985, a rewind that breaks with previous versions of the show, which left off in the mid-90s. The narrator, who speaks to us with hindsight from the present day, acknowledges what we all already know: The 1980s drug war we’ll see depicted in these episodes is still raging south of the United States border. Don’t expect this to be a tidy arc. It’s a reality that hits a little too close to home with regards to this show. Last year, one of its location scouts was found shot to death in Mexico amid what was shaping up to be the country’s deadliest year.

The first two seasons of the show focused on Pablo Escobar, the former kingpin in charge of the Medellin cartel in Colombia. But it started with Escobar already in power, rather than with his beginnings. Anyone with even a cursory knowledge of history knew that Escobar was killed in a rooftop shootout in the 1990s. But the show was compelling regardless, mostly because of the simultaneous humanity and depravity Wagner Moura brought in spades to portraying Escobar. Moura, much like James Gandolfini and Bryan Cranston, was able to force the audience to catch itself in often rooting for a complex monster.

In Season 3, “Narcos” surpassed expectations in a post-Escobar universe, shifting focus to the Cali cartel that filled the vacuum left behind by Escobar’s death: Its four charismatic leaders were equally monstrous, but they had more flair. It helped that Pedro Pascal’s Javier Peña was a compelling leading man, whose frustration with the drug war becomes more evident with each passing episode.