The creator Thomas Brandon (“Legacies”) and his writers’ penchant for time shifts — two hours ago, eleven months before, yesterday — can make the complicated plot hard to follow and lead to binging vertigo. And yet, it satisfies our spy TV jones, and Liu passes the test as a dynamic leading man.

The Copenhagen Test is an engaging, entertaining spy thriller with a sci-fi edge. Liu serves as a strong lead for the series, boasting strong action chops and great chemistry with Barrera.

“The Copenhagen Test” provides pleasures enough to warrant an advisory: Slog through episode 1. It may seem disjointed and misdirected, with people in backgrounds moving like robots (not a spoiler) and a plotline that’s almost deliberately arcane. Just chalk it up to the curse of the eight-part suspense-thriller: There is time to throw a bunch of messy stuff against the wall. By episode 2, it congeals into something like a coherent picture.

A few noteworthy performances aside, The Copenhagen Test leaves hardly any room for its character to breathe.

Unfortunately, through its first four episodes, The Copenhagen Test is also a wonderful sleep aid — a whole lot of leaden dialogue and convoluted plotting, with very little intensity or momentum. It does get better, mind you. .... The last two episodes give the first real indications that the show is capable of being smartly tricky with its structure and timeline, rather than just annoyingly evasive.

Like most eight-hour dramas, it’s too long — “Slow Horses,” the best of this breed, sticks to six — and over the course of the show, things grow muddied with MacGuffins and subplots. While it’s easy enough to enjoy what’s happening in the moment, it can be easy to lose the plot and harder to tell just who’s on what side, or even how many sides there are.

Overall, "The Copenhagen Test" will likely serve as nothing more than a pit stop in all of these actors' careers, utterly forgettable and hardly worth mentioning.