The producers of “Killing Eve” have announced that the upcoming fourth season of the show will be its last. They should have made that decision after its first year.

There are many series that had dynamite debut seasons, created a lot of buzz, and attracted loyal audiences, yet started to go downhill as soon as everyone involved decided to continue the story. In truth, those shows had great concepts and casts, but not enough storyline to drag things out (e.g. “Bloodline,” “Sneaky Pete,” and “Homeland”).

“Killing Eve” was just such a show. Its opening plot, about an American working for Britain’s MI-6 while on the hunt for a serial killer, was masterfully executed. Sandra Oh struck just the right chord as protagonist Eve Polastri, and Jodie Comer was spectacular as antagonist Villanelle, an assassin who not only enjoyed her work, but pulled off her jobs with a high level of cleverness and disdain for social mores. Both actresses and the show (as well as writers, directors, production designers, and editors) won or were nominated for all sorts of awards.

When it returned, the proceedings very quickly got bogged down by subplots about Eve’s home life and from whom Villanelle got her orders.

One of the things that hurt “Killing Eve” was that the showrunner changed each season. Phoebe Waller-Bridge created the show and oversaw its impressive first year. By that point, Waller-Bridge’s other project, “Fleabag,” had also become a success, so she handed the reins of “Killing Eve” over to Emerald Fennel, who then left to make the Carey Mulligan movie, “Promising Young Woman” (which I raved about here). “Killing Eve” then was passed to Suzanne Heathcote for the third season and Laura Neal for the fourth. Talented as each of those women may be, they lost the thread of what made the cat-and-mouse adventures of the two leads so enjoyable, to the point of even teaming them up to work together.

That’s when “Killing Eve,” a show I once considered must-see TV — when each hour ended, I couldn’t wait to see what happened the following week — lost me. To make matters worse, the fourth season won’t debut on AMC until sometime in 2022, two years after it last aired. Meanwhile, I’ve gotten caught up in so many other binge-worthy TV series that I’ve completely forgotten what Eve and Villanelle were up to. And I’m not sure I care anymore.