It's about fire fighters, in a world where spontaneous combustion can kill you at any time and turn you into creepy burning undead (Infernals). Fortunately, most of those fire fighters are pyrokinetics. That might not sound like what you'd want in fire fighters, but it's super-useful (and looks cool). Second-generation pyrokinetics can control existing flames. Third-generation ones can create their own flames and use them for flight, combat, etc.
Oh, and the Earth was rendered mostly uninhabitable 250 years ago, by the Great Disaster. Our heroes live in the Tokyo Empire, which has its own religion (the Holy Sol Temple) and a supply of perpetual free energy thanks to the Amaterasu power plant, maintained by Haijima Industries. As for the empire's Fire Force, that's run by eight fiercely territorial companies that are capable of treating each other as enemies.
The first few episodes take all this at face value. Before long, though, we learn that our heroes have enemies in directions they hadn't expected.
Would I recommend this season? Dunno. It has a hiccup around ep.8, but it's mostly okay. Will I watch Season 2? Probably, but I wouldn't lose any sleep if I didn't. It's a shounen series, falling into the same category as Bleach, Naruto, etc. There's lots of action, but the show's not actually fight-driven. It's not Dragonball. What's more, the action scenes are often impressive (e.g. ep.7) and it's a good-looking series all round.
The writing is passable. I didn't mind the season, but I was more interested in its second half than its first. New characters make the show livelier, e.g. Vulcan, Lisa and the company heads like Benimaru. Also, importantly, the show grows proper villains. The Evangelist and White Clad give the show focus.
The female characters don't fare well. That's not unusual in shounen anime, admittedly, and it's not as bad as, say, Nezuko in Kimetsu no Yaiba. There's even a fair amount of gender balance, with Tamaki, Maki and Sister Iris... but it's the boys who matter. Shinra's the main hero. Arthur is his childhood friend and idiot foil. Everyone else is back-up. Ep.19 lets the girls be the action heroes for once, but that's very much the exception. Meanwhile, Tamaki is a "lucky lecher lure", i.e. horrible luck keeps putting her in (laughably tame) fanservice situations. I'd have had more sympathy if it weren't for that bikini top. If you're prone to wardrobe malfunctions, dress in a way that doesn't invite wardrobe malfunctions. I've seen it claimed that she needs to show skin to use her superpowers... but I'll be damned if I can remember why, or how, or indeed what those powers are, or whether we've ever seen her using them.
Usually, Tamaki just feels like another example of the show's default characterisation mode of "comedy idiot". See also Maki's "gorilla cyclops" fixation, or everything Arthur says and does. I don't mind that. It's amusing. What's not funny at all is the tonal problems circa ep.8. A baddie is burning to death a group of children and mothers one by one, while also beating up and kicking a woman who loved him. Shocking? Yes, but for the wrong reasons. The baddie's a cartoonish ham who makes the scene look silly, which made me itchy given the content, while the psychic fire fighter he's kicking just gets kicked a lot and doesn't try to fight back. (I get the "loves him" thing, but even so it's surprising that she's not trying to protect the children.) Ultimately, she gets her clothes burned off and has to get rescued by a male hero.
There's no defending that bit. Whether or not you like this show, that was an ugly low point.
That said, though, there are also things I like here.
I like the religious angle. A nun accompanies the fire fighters on their missions to perform the last rites, because killing an infernal is about laying the dead to rest. I liked the moments of compassion with the bereaved. I approved of our idiot heroes getting told off in ep.2 for insensitivity, because they're executioners as well as soldiers. I also liked rebuilding burned houses and playing with children in ep.12.
I also quite like our halfwitted heroes. "King Arthur" is one of the most magnificent idiots you've ever seen, especially in ep.16. He's so dumb that he can forget which hand he uses to hold a sword.
I also like the fire fighters' uniforms. They're so huge and clunky that they're sort of brilliant. They resemble limpets with clunky blue stripes... yet that's actually quite an accurate portrayal of Japanese fire fighters' uniforms.
Overall, this is a sort-of-okay series that struggles up to "actually quite good sometimes" in the second half. It has one bad misstep, but at other times it can be charming. The action scenes look fantastic. I can't see myself ever rewatching it, but I'll probably continue with Season 2.