The general idea behind The Magicians is that magic is real, but hidden from normal people. There's a hidden magical university in upstate New York called Brakebills where magicians are trained. Yes, that's basically Harry Potter on the other side of the Atlantic, but much more worldly. The characters are college-aged and fully aware of (and engaged in) drinking, drugs, and sex. Brakebills isn't entirely filled with good guys, and those outside it aren't entirely bad. The magic-versus-muggles part is more or less the same, though.
The Magicians also borrows from another classic fantasy work in its use of a magical world called Fillory, which shares a whole lot with Narnia. Fillory turns out to be pretty dangerous, which I suppose isn't entirely unlike Narnia, but it certainly feels much darker. That's true of the entire show, in Fillory or elsewhere. It's not quite full-on horror, but there are plenty of dark and frightening elements, from psychological breakdowns to haunted houses to a mysterious and murderous Beast.
I wasn't greatly impressed with any of the primary characters at first, but some of them have grown on me as I got further into the episodes. I think that's largely because there's so many: Quentin is clearly the main protagonist, then there's his childhood crush Julia, his classmate and eventual girlfriend Alice, and four other classmates that have extensive roles. That's a whole lot of development needed to connect the viewer to each one. That makes for some early confusion, but by about halfway through the season, their motivations and personalities were mostly clear. You definitely want to watch this series all the way through from the beginning, as otherwise much of how the characters act won't make sense. There's too much going on in their heads to fill in the gaps from missed episodes by context.
Events progress through this first season fairly quickly, with a lot happening in just about every episode. Some parts move almost too quickly, such as Julia rising through the ranks of a "hedge witch" group practically overnight. There are only 13 episodes, which is more like half a season than a full one, so that's not entirely unexpected. The story is kept interesting even as it moves quickly, with a "big mystery" aspect set up in the very first episode with the first appearance of the Beast. I think the pacing is done well, considering the limitations of such a short season format.
The Magicians has a very worldly feel with plenty of adult themes, so it's probably not for everyone that likes Harry Potter or Narnia (particularly younger folks). But if a darker take on those magical fantasy worlds sounds interesting to you, then The Magicians is well worth a look.
