After four years without the familiar ticking clock sound, 24 returns to Fox tonight for the two hour premiere of Live Another Day.

24: Live Another Day seems to have been around in the cultural consciousness for years now. It’s been subject to fascinating essays about what the new 12-episode “TV event” means for traditional network 22-25 episode programming and how it will reflect the post-post 9/11 world.

But as of tonight at 8 p.m., 24: Live Another Day returns to the airwaves as a TV show, not a thinkpiece.

Here is everything you need to know to get back into the high-octane and at times logic-defying world of Jack Bauer.

24 Hours in 12: The New Format

For as large as Jack Bauer looms as a cultural icon now, the real star of 24 was always time itself. For 8 seasons, the show presented its plot in realtime, covering a 24-hour day, save for commerical (and presumably potty) breaks.

24: Live Another Day will preserve this real-time format, with a little twist. One episode of the show will still cover one-hour, the action will just halt at 12 hours instead of 24. Episode 1 is titled, “Day 9: 11:00 a.m. – 12:00 p.m.” while episode two is “Day 9: 12:00 p.m. – 1:00 p.m.” and so on. This, of course, makes the name “24” charmingly irrelevant but should produce a much tighter show.

Anarchy in the U.K.: Jack in London

Jack Bauer fought terrorists from the safe filming confines of Los Angeles for two seasons before stopping by Washington D.C. and New York in the final two seasons. Now he’s getting out of the U.S. entirely as season 9 is set in London.*

The reasons are two-fold. For starters, Jack isn’t necessarily welcome back in the U.S. any more after betraying his country. And secondly…it had to be a lot of fun filming in Great Britain.

The main plot of Live Another Day concerns Jack halting the assassination of the American President on foreign soil.

*This isn’t the first time 24 went international but it is the first time the action will take place in a real non-American city for a full season. Season 3 had a pit stop in Mexico and the TV movie, 24: Redemption was set in a fictional African country.

Returning Characters

Jack Bauer (Kiefer Sutherland) – Well this one isn’t a surprise. No Jack, no show. Here is what Sutherland had to say about his character’s mindset going into the season.

On a much more kind of intimate character level, Jack Bauer is just, he’s harder and I think angrier than he’s ever been. He’s had to hide in Eastern Europe for four years, he’s been estranged from his daughter and his grandchildren, he has not been able to go back to the country that he feels he served, and that kind of isolation has made him really hard.

Chloe O’Brien (Mary Lynn Rajskub) – Chloe is arguably the only other indispensable character on 24 aside from Jack. She helped Jack escape the country following season 8’s “series” finale and paid a huge price. Live Another Day finds her in a dark place…with excellent bangs.

Audrey Raines (Kim Raver) – Audrey was first introduced as a love interest to Jack in season 4, but as things often do for people Jack cares about: everything quickly went to hell. Now that Jack is trying to protect her father’s life, their paths may cross again. She is currently married to her father’s Chief of Staff, Mark Boudreau (Tate Donovan).

President James Heller (William Devane) – Once the U.S. Secretary of Defense who employed Jack, Heller is now the President of the United States. A threat against his life brings Jack back into the fold.

New Faces

Kate Morgan (Yvonne Strahovski) – Producers have described CIA field agent Kate Morgan as Jack’s mirror image in many ways. Popular genre actress Yvonne Strahovski looks to have the gravitas to match up well with Kiefer Sutherland.

Adrian Cross (Michael Wincott) – Just as the first 8 seasons of 24 reflected the political landscape, season 9 should do the same according to the show’s producers. This means plenty of Snowden-style computer hacker-y. Enter Adrian Cross, leader of a free information movement.

Erik Ritter (Gbenga Akinnagbe) – Ritter is another CIA operative on the lookout for Jack Bauer. Akinnagbe was previously best known as the cruel Chris Partlow on The Wire.

Prime Minister Alastair Davies (Stephen Fry) – Comedy legend and general all-around All-Star British person Stephen Fry will be depicting the British P.M…finally. Much of season 9 involves Anglo-American relations, so expect plenty of scenes with Fry lounging at 10 Downing Street.

Steve Navarro (Benjamin Bratt) – Navarro is the head of the CIA Operations tracking Jack across the world. He likely does not know what he’s got himself into.

Margot Al-Harazi (Michelle Fairley) – Game of Thrones alum Michelle Fairley plays the widow of a notorious terrorist. 24 has depicted terrorists in nearly every possible way for eight-plus years but still this seems to be a new one.

Limited Series – A New ‘Day’

Network TV seems to be catching up with its cable brethren in wanting shorter, more compact series. It’s a lot easier to sustain momentum and suspense over a 13-episode Breaking Bad season than a 24-episode 24.

In many ways, 24: Live Another Day is the largest experiment yet for how successful that model can be. Early reviews have been positive so check it out tonight to see if 12 is the new 24.