Time travel is one of the trickiest tools a writer can pick up. It’s a genre that demands discipline. Every rule you set has to be followed. Get it wrong, and you end up with a tangled mess of plot holes that fans will spend years picking apart. When it comes to movies, filmmakers have gotten it right more times than you can count. Back to the Future basically wrote the rulebook. Then there’s Terminator. <em>Primer</em>. Predestination. Edge of Tomorrow. Avengers: Endgame. Hot Tub Time Machine. The list goes on and on.

Television, however, is a different story. Building a TV series around the concept is an entirely different challenge because writers have to keep their rules consistent across dozens of episodes and multiple seasons. It’s no surprise, then, that there are far fewer great time travel shows than there are movies. The ones that do succeed, though, are some of the smartest and most ambitious sci-fi stories ever made. Here are the greatest sci-fi series that deal with time travel.

‘Continuum’ (2012–2015)

Continuum follows Kiera Cameron (Rachel Nichols), a cop from the year 2077, where the world is run by a corporate governing body called the Corporate Congress. When a group of terrorists known as Liber8 get sent back in time to escape execution, Kiera gets dragged along with them and ends up stranded in 2012 Vancouver. With no way home and no backup, she teams up with a local detective and starts hunting down the Liber8 members one by one, all while hiding the fact that she’s from six decades in the future.

What makes Continuum so compelling is that it never lets you fully root for either side. Kiera is fighting to protect a future that is, by almost every measure, a dystopia, and the terrorists she’s chasing genuinely believe they’re stopping that future from happening. As the show goes on, Kiera slowly starts realizing that every choice she makes to get home might be reshaping the very future she’s trying to save. It’s a show that trusts its audience to keep up, and it rewards that trust with one of the most underrated sci-fi mysteries of the 2010s.

‘The Lazarus Project’ (2022–2023)

Paapa Essiedu stars as George, an ordinary app developer whose life gets turned upside down when he suddenly wakes up six months ago, back in July. At first, it plays like a <em>Groundhog Day </em>setup, but the show quickly reveals what’s really going on. George gets recruited by the Lazarus Project, a covert agency with the power to roll back time to the most recent checkpoint whenever humanity is on the brink of annihilation.

There’s one catch, though. They can only rewind time to the most recent July 1, which means every reset forces them to relive months of their lives from scratch. And things become even more complicated when George’s wife dies in a tragic accident. Refusing to accept her fate, he breaks the agency’s most important rule and manipulates events to trigger a time reset, which sets off a chain reaction that threatens both the organization and reality itself.

‘The Flash’ (2014–2023)

When Barry Allen ( Grant Gustin ) was 11 , he watched a yellow blur kill his mother , alongside a mysterious red blur he couldn’t explain . His father gets wrongfully convicted for the murder , and that injustice is what pushes Barry to become a crime scene investigator determined to clear his dad’s name . Then ,a freak particle accelerator explosion gives Barry superhuman speed and unleashes metahumans across Central City , and Barry starts using his powers to protect the city as the Flash .