I just watched the first two episodes, available for free on YouTube. It's a prequel, dated ten years before the first episode of the original series. The Enterprise is commanded by Captain Pike, and most of the characters from the original series are there as well, including a young Kirk and Spock.
I really enjoyed it, and I think fans of the franchise will, too if you're not a "Trekkie," many of the in-universe references will go over your head. But it's enjoyable as it stands.
I hope Paramount makes further episodes available.