Netflix has acquired streaming rights for all the Star Trek television series, and plans to roll them out toward the end of the year. Good news for fans, definitely, but what if you've never seen any of the five shows and your time is limited? Don't worry: We'll tell you the 20 episodes you should make room in your schedule to see.

Star Trek

The original - and, I'd argue, still the best --- of all Star Trek series, Trek ran just three seasons, from 1966 through 1969, but nonetheless set the tone for everything that came afterward ... well, almost. For one thing, Trek is funnier than every other series in the franchise, and also more willing to let its heroes be idiots when the situation demands. Here are four episodes that pretty much sum up what this series has to offer:

Where No Man Has Gone Before

The second pilot for the series, after the original was deemed "too cerebral," this episode lays out the Trek worldview pretty clearly, with the idea of man coming face to face with powers and beings beyond his understanding -- only to get into a fistfight with them -- being central to the episode, and the show. But as well as the science fiction and two-fisted action, there's a tragic side as well, and somewhere in the combination of all three is where Trek really exists.

The City on The Edge of Forever

One of the best episodes of any science-fiction television series, the time-traveling "City" again brings the tragedy -- history can't be changed, even for love! -- and also gives Trek the chance to do what it enjoyed doing every now and again ... Namely, play dress-up. Seeing Spock, Bones and Kirk in Depression-era New York manages to reinvigorate the characters, while reinforcing the point of view that makes the series so great.

Mirror, Mirror

Parallel universes (and the origin of the evil-twin-has-a-goatee meme)! Political science (well, after a fashion)! The universal power of logic! This one really does have it all, true believers. A really spectacular hour of television.

Turnabout Intruder

I mention this, I admit, not because it's one of the best episodes of the show -- it is, actually, the last episode aired during the show's original run, and features a fun-but-not-groundbreaking plot about Kirk's consciousness being swapped with a woman intent on killing him -- but because, for a remarkable number of people I know, this was the first episode of the show they ever saw, and they were immediately hooked. I don't know why, but I can attest to its power: This was my first Trek, and I had to see more once it was over.

Star Trek: The Next Generation

Cut to almost 20 years after the cancellation of the first series, and The Next Generation was introduced, thanks to Trek's continuing success as a movie franchise. After a couple of rough early years -- seriously, that second year is appalling -- the show found its feet by Season 3, and fans loved it, even if I don't think it's aged so well. Anyway: Four episodes!

Yesterday's Enterprise

The show plays with a similar conceit to the original series' "City On The Edge of Forever," but this time it's something from the past entering the present that changes everything -- and we get to see all the changes for ourselves. With an altered timeline offering dramatic possibilities an ongoing series wouldn't, there's something incredibly satisfying in seeing the show go for broke knowing that it wouldn't necessarily have to pick up the pieces afterward.

The Best Of Both Worlds

Yes, I know this is technically cheating as it's one story split across two episodes, but this season-ending cliffhanger and its conclusion managed to successfully up the stakes for its duration, keeping everyone on their toes about whether everyone would survive, and even if they did, how an unbeatable foe could be defeated. For a show that could at times become too talky and self-referential, this is a ridiculously exciting story.

Conundrum

Taking all of your characters' memories away in one fell swoop doesn't just allow for some rare humor in this series -- it delivers on that front ably, though -- but it also offers up a great mystery as the viewers and cast have to work out how it happened, and why. The pay-off is surprisingly worth it.

All Good Things

It's rare for a show that runs for seven years to have a finale that pretty much perfectly sums up what the show was about and what made it work. However, "All Good Things" is that rare thing, an almost-perfect finale that calls back to the very first episode and everything in between without feeling too self-conscious, self-aware or sentimental. Never mind Generations, this should have been the cast's first movie.

Star Trek: Deep Space Nine

I'll admit, this is probably my favorite Trek series outside of the original, and that's in large part because it's such a break from the routine. Setting it on a stationary location -- a space station in the middle of politically disputed territory -- and with a hero who isn't sure he is a hero seemed like revolutionary behavior back in the day, and I think science-fiction television is all the better for it. So, four episodes from DS9, then:

Emissary

The first episode, and pretty much necessary for anyone who wants to try and understand what the series is about, mixing politics, religion and all things Star Trek to come up with ... well, something that makes you believe that Ron Moore of Battlestar Galactica fame worked on this show for some years, really.

Duet

World War II allusions abound as a visiting alien is suspected as a war criminal, and one of the space station's crew decides she will expose him. However, the subject is treated with a surprising lightness of touch, even if the finale goes a little bit toward the unsubtle moral-of-the-week side.

Trials and Tribble-ations

Broad comedy to celebrate the franchise's 30th anniversary, as the cast go back in time to the original series, and finds itself cut into an actual episode of the original series, offering snark and Rosencrantz-and-Guildenstern-style commentary on the action.

Far Beyond The Stars

I'm not the greatest fan of episodes that excitedly ask "What if everything you've seen before has only been someone's dream?" but this one does so remarkably well, and with a particularly poignancy, casting Captain Sisko back to the 1950s, where he may (or may not) have been a successful science fiction writer dreaming everything up.

Star Trek: Voyager

By now, the franchise was beginning to run out of steam, and this "lost in space" series seemed less sure of itself for its entire run, especially when it tried to reboot itself halfway through with the introduction of Jeri Ryan in tight, tight outfits. But that doesn't mean it's all bad. Here are four episodes to prove it:

Deadlock

Voyager liked to mess with viewers' heads a lot: Characters would become mutated by traveling at speeds beyond imagination, merged by teleportation accidents or, in this episode, somehow cloned and facing themselves with neither knowing which is the "real" crew.

Year of Hell

Talking of messing with heads, this two-part episode pretty much put the entire cast -- and the audience -- through the ringer before coming up with a fun solution on how to fix things that has to be seen to be believed.

Live Fast and Prosper

For once, the franchise really addresses the idea that its heroes are heroes by having con men impersonate them and leave behind a trail of disaster for the real crew to deal with. Funny, if self-referential, and a nice break from the melodrama that the show would eventually become.

Endgame

Another final episode that actually fits with the rest of the series, this one isn't as perfect as "All Good Things," but at least manages to continue with the temporal screwiness by centering around an attempt by a future version of the Captain to change her past by bringing her crew home early. Voyager: A series that never wanted to settle for reality the way it was.

Star Trek: Enterprise

I think it's fair to say that Enterprise may have been well-intentioned, but the execution was more than a little ... not-so-good. It's also the only series in the franchise to get canceled, as opposed to end on the creators' own terms, outside of the original. But, still, that final season wasn't too shabby ...

Similitude

Moral questions over cloning are addressed in this episode where a clone is created for spare parts to help heal an injured crewman, but not everyone is on board with killing the clone to harvest those parts. Torn from the headlines -- if not exactly treated with the greatest amount of realism.

Vanishing Point

Thanks to a transporter accident, one of the crew starts turning invisible and everyone else thinks she's dead. One for paranoid fans especially, it's one of the more subtle episodes from the show's earlier seasons, and enjoyably tense.

Bound

Fan service never felt so guilty as it did here, in an episode constructed pretty much to take advantage of the fan love for a minor character, the green-skinned Orion slave girl, from the original series. It's cheap, it's tacky, but ... it's also kind of fun, in a terrible way.

In A Mirror, Darkly

Yes, it's pretty much just a retread of the "Mirror, Mirror" episode of Star Trek, but again, the fan service is enough to make this one of the best stories (again, it's a two-part episode) of the series. If nothing else, seeing the crew in the colorful costumes of the original series is kind of awesome.