IT’S DECEMBER 1995, San Francisco. Evan wakes up dribbling and confused in the back of a Land Rover in an underground car park, just as the car starts to move. We discover that he climbed in after slinking away from a party at ForwardSlash, a “new media” company celebrating its stock flotation. People are getting rich, and Evan is a bit of a mess.

We flash back a year, and John Butler’s debut novel gets into its stride in more familiar territory. Evan is an innocent and not very self-aware middle-class Dublin boy who gets out of University College Dublin and heads for the US with his best friend, Milo, with nothing very much in mind other than maybe getting a job in television.

There are two stories here. The first is specific to time and place, concerning the inflating of the 1990s technology bubble and the rise to power in California of the coders and internet evangelists, poised to make as much money as they can before the thing bursts. And Butler tells us about this, but it’s not very interesting and he seems to sidetrack to do it. Evan is our narrator, and there is a little too much slightly anachronistic editorialising about the shift online and the changes it brings to San Francisco’s subcultures – simplistically put, from hippy to geek. So we get the launch of Windows 95, the death of Jerry Garcia and, during the party at the beginning, a speech to the employee shareholders about the lessons to be learned from the failure and imminent collapse of that hardware dinosaur Apple.

The other story, Evan’s story, is the real heart of the book. After all, he’s just a runner and handyman at ForwardSlash, and he doesn’t really know what he’s doing there. He’s familiar to us: the young man who is clueless about most things, most painfully about himself, and who has to learn the basic lessons about who he is, in his own awkward and flailing way. He has plenty to overcome, most of it related to his childhood and his relationship with the more handsome, more (dumbly) adventurous Milo, and Milo’s parents, and Milo’s girlfriend, Róisín.

These Dublin hang-ups follow Evan, literally. Róisín shows up and the two become entangled in an uneasy hide-and-seek sort of friendship, and at one point Milo’s parents arrive for a family summit disguised as a holiday.

Evan’s relentless virginity in the face of all that San Francisco has to offer, and his growing fascination with middle-aged, married Sam Couples, the boss of ForwardSlash (and the owner of the Land Rover), points us towards what all this may be about. But Evan is way behind us. And there is a certain tedium involved in waiting for him to catch up.

This isn’t helped by the bagginess of the writing at times. There is a pointless and invasive epilogue, but, throughout, there is an anxiety about the mechanics of organisation, so that we get, for example, a lot of unnecessary street names and directions, and clarification and detail that are superfluous and distracting.

Part of this is down to the decision to make this a first-person narration. Evan is his own problem, and more distance might have sharpened the focus, as well as allowing Butler more space to include the wider context more authentically, rather than squeezing it into Evan’s perspective.

Not that Evan’s perspective is uninteresting. There are some affecting understated passages about drinking too much, about taking too many drugs – or the wrong drugs – and especially about (sober) fear and loneliness. But these are too brief, and too widely dispersed in what is in large part an unsurprising, conventional narrative.

There is in The Tenderloin  a shorter and better book fighting to get out. Much as there is a sharper, more relaxed Evan struggling to emerge from the annoying and uptight suburban Dublin boy whom you will spend most of this book wanting to slap.

Butler does some things beautifully. He writes well about the undulating environment of San Francisco. There is a marvellous section set in a records office where Evan temps for a while. The dialogue rings true, as do the distinctive minor characters, and there are a couple of memorable set pieces: a slightly predictable one involving an ice sculpture, and a great uneasy escapade on Sam Couples’s boat.

The ending (ignoring the epilogue), which comes when we get back to that mysterious ride in the Land Rover, is terrific. And it suggests that Butler has a real instinct for writing about the derailed ego and those mortifying moments of absurd crisis that hit the reader like a dreadful painful whack on the funny bone.

More of that, and less of the urge to document, would have been welcome.