Tranquility Base Hotel & Casino, the sixth Arctic Monkeys album, opens with tinkly pianos, brushed drums, murmuring vintage synths, and this line: “I just wanted to be one of the Strokes / Now look at the mess you made me make.” Alex Turner delivers it in a quavery, knowingly drunk open-shirt-collar slur, his voice slathered in echo. It’s a great opening line, smirky and self-aware and attention-grabbing. And when viewed in the right light, it looks like a statement of intent. But really, the line from the album that reads as the thesis statement, the one that tells you everything you need to know about what Turner and his band are doing, shows up on “One Point Perspective,” the album’s second song. It’s this: “Bear with me, man, I lost my train of thought.”

Tranquility Base is a lyrics-first album if ever there was one, and those lyrics represent one lost train of thought after another. In interviews, Turner has said that it’s a concept album of sorts, based on the idea of an expensive luxury resort on the moon, located on the exact spot where the 1969 moon landing touched down, one that’s maybe become a high-class sleazy swingers’ getaway, like a futuristic version of Rat Pack-era Vegas during an era of earthly environmental catastrophe. That’s a fun idea, one full of images of ecological degradation and deep division between classes and self-destructive rich-kid decadence. But the problem is that Turner can’t commit to the bit. He can’t even bring himself to focus on the bit for more than a line or two at a time.

All through the album, Turner gets lost in his own lyrical asides, in digressions and half-thoughts. “What do you mean, you’ve never seen Blade Runner?,” he explodes at one point, apropos of nothing. Since Turner was a teenager, he’s been one of rock’s sharpest lyricists, capable of cramming finely hewn social observations into dance-rock bangers or stoner dirges. And there are great lines on Tranquility Base: “Everybody’s on a barge floating down the endless stream of great TV,” “And all of my most muscular regrets explode behind my eyes like American sports.” The impersonal numbness of internet communication is well-trod ground, but I still like the way Turner writes about it: “Finally, I can share with you through cloudy skies / Every whimsical thought that enters my mind / There ain’t no limit to the length of the dickheads we could be.”

Still, those great lines are disconnected and idle — thrown-off asides that add up to nothing. And there are plenty of fucking howlers, too. Trust Turner, for instance, to come up with the same bone-basic political observations that everyone was sick of tweeting two years ago: “The leader of the free world reminds you of a wrestler wearing tight golden trunks.” Or consider a tangled piece of linguistic ugliness like this: “Kiss me underneath the moon’s sideboob.” Some of the most damning examples, I think, show up on the song “Science Fiction,” which aspires to be science fiction but which is really just about science fiction. See, sci-fi has long been a refuge for subversive thinkers looking for oblique ways to address the problems of the day — think of Rod Serling, using a planet full of apes as a parable for senseless racial hierarchies and species-wide self-destructive urges. That’s clearly what Turner wants to do with Tranquility Base, but he can’t resist setting up signs with blinking arrows that point to what he’s doing: “Highlight dangers and send out hidden messages / The way some science fiction does.”

I’ve used up all this space writing about Turner’s lyrics mostly because the music is such a drag that it’s not even fun to think about. Since their inception, Arctic Monkeys have done an admirable job switching things up stylistically from album to album, veering from brittle terseness to desert doom in the space of one between-LPs break. But in their last two albums, 2011’s Suck It And See and 2013’s AM, the band really honed their attack, becoming a tough and efficient delivery system for nasty hooks and reptilian swagger. In the process, they became monstrous, larger-than-life, global rock stars, the type who just do not come around anymore.

Tranquility Base represents a total left-turn, and that’s certainly a brave step, maybe one to be admired. Turner has said that he wrote the album’s songs on piano for the first time, and he’s definitely been thinking about a long lineage of satirical and self-obsessed pop-music gentlemen, one that stretches from Leonard Cohen and David Bowie all the way through to Father John Misty. But the sound of Tranquility Base, while cohesive and fully formed, is also a half-baked slog, a snoozy and self-indulgent wallow in lounge-lizard affectations. Turner’s sophisticated-dirtbag pose is fun enough, but his fellow Sheffield native Jarvis Cocker did it better on This Is Hardcore. And This Is Hardcore had songs.

It’s an ambitious mess, certainly. The Arctic Monkeys of Tranquility Base draw from jazz and soul and early-’70s French pop and far-out synth-prog. And the band plays around with these sounds impressively; drummer Matt Helders, once such an effective bomb-dropper, has adapted beautifully to the syncopated brush-flourishes that the new sound demands, and the old-timey analog-keyboard wails are gorgeously rendered. But it’s still a mess. The songs just aren’t there. The band has imposed no restraints on Turner’s free-wandering musings, and the guy can barely drag himself back to the melody long enough to utter something that could pass as a chorus. Maybe that’s why the band hasn’t shared any advance singles — not because they want to keep things mysterious but because the whole thing plays out as one long and interminable song, no hooks anywhere.

Again, that’s a daring move, and it’s one that they’ve fleshed out as well as they can. It’s a complete break from the band’s past and a full-on dive into a sound they’ve never attempted before. My wife overheard me playing it a few days ago and asked if I was listening to Lambchop. And she was totally right; Tranquility Base sounds a lot like Lambchop. Depending on your perspective, that could be a bad thing. (I like Lambchop fine.) But even if you love Lambchop, do really want to see this once-exciting livewire act, the youngest old-school festival-headliner rock stars in the world, making a Lambchop album?

The two albums sound nothing alike, but the comparison that keeps occurring to me when I’m listening to Tranquility Base is Arcade Fire’s Everything Now — another album from a huge band that tries new musical ideas while attempting to skewer the perceived excesses of our present-day social-media reality. In both cases, it’s easy enough to imagine better versions of the albums existing. They have noble aims, and yet they come off as pretentious thrashings, full of concepts that haven’t been given the room to become fully formed ideas. There’s the seed of something here, but that seed has not grown. Maybe the band needed to think Tranquility Base through a little more. But then, maybe they lost their train of thought.

Tranquility Base Hotel & Casino is out 5/11 on Domino.

UPDATE: Here’s the stream…