“Just so you know” is a phrase you hear a lot when you're dealing with Little Sister in Manhattan Beach.

“Just so you know, we only hold reservations for 15 minutes,” the hostess says, somewhat threateningly, when she calls to confirm.

“Just so you know, we don't have a kids menu,” the waitress says, sounding combative, although no kids menu has been requested. “And just so you know? The food will come out whenever it's ready.”

See more of Anne Fishbein's photos of Little Sister.

In Little Sister's defense, being the hippest restaurant in Manhattan Beach is a hard row to hoe. It's perhaps a steep learning curve for customers to go from casual upscale beach dining to a dimly lit room with a profane hip-hop soundtrack. That's certainly the impression you get, and not just from the multiple waitstaff disclaimers. Much of the bewildered-looking clientele can be seen employing their phone flashlights to read the menu, and asking waiters why the sake isn't served hot and could they please recommend some dishes that aren't too spicy?

Little Sister's older sibling is Abigaile, a sprawling Hermosa Beach gastropub, which has the same owners and chef. But where Abigaile's offerings veer toward escargot poppers and bacon Bolognese, Little Sister is serving food that feels closer to chef Tin Vuong's heart.

Southeast Asia is a lot of ground to cover, flavorwise. Who else but a San Gabriel Valley–raised chef, trained in economics (at college) and cooking (at culinary school), to show Manhattan Beach the genre's possibilities, small plates–style?

So you'll sit under the back-wall mural of a machine gun spewing vivid butterflies and eat Vietnamese crepes and Myanmar curries and Sichuan noodles and Balinese meatballs. And to your surprise, despite the trendy digs, beyond the almost-obnoxious service, all those things will be bloody delicious.

While some of the culinary acrobatics Vuong shows off at Abigaile make their way onto the plate here as well, this is not cute American food with Asian accents. There's a purity of intention that shines through. Dishes are boldly spicy where appropriate, unapologetically funky, bursting with flavor.

Those Sichuan noodles come swimming in a sauce of musky lamb, with pea shoot tendrils, roasted peanuts and a slow burn that builds as you slurp. The Burmese curry swathes its okra in a beguiling sweet sauce, built from tomato and tamarind and complex spicing. Kima platha, a crisp, pocketlike flatbread stuffed with ground chili-infused lamb, comes atop a rich, coconut curry lentil sauce.

A section of the menu is dedicated to “Eastside 626 Provisions,” a collection of condiments and international banchan. You could make a meal from this alone: flowering jasmine rice; ma la pickles that are sweet and prickly with Sichuan peppercorns; fried okra with tomato, lime and fenugreek; aggressively fiery green mango with tamarind, guava and chiles.

The crisp Vietnamese crepes overflow with pork belly, prawns and bean sprouts, and come with a pile of lettuce and herbs for wrapping and cool accompaniment. Pea tendrils zing with lime and get a kick of oceanic umami from the addition of dried scallop shards.

Even when Vuong plays games of multicultural mash-up, it works. The tenderest duck you've ever had comes as a satay, the skewers resting over caramelized pear and almonds. Pear also shows up in the beef tartare, along with pine nuts and bone marrow vinaigrette. And a quail dish is raucously international in scope — Indian-spiced, served with Middle Eastern–style yogurt, mint chutney, pickled kumquat, and fried green tomatoes straight out of the Southern repertoire.

There's the occasional slip in execution, like overcooked “charred” shrimp, which came with a heap of green papaya salad. The mistreatment was all the more frustrating because the shrimp were so fabulously spiced.

And while the dessert setup is surely fun — for $10 you choose three items from a list, and the mini desserts come lined up on the plate — I found offerings like brown butter pear tart and peanut butter profiterole better in theory than in practice. This might be one place where Vuong's penchant for complexity goes awry.

In many ways, this is food that demands cocktails — or at least a restaurant that seems as though it ought to be serving cocktails. But the license is for beer and wine only.

Not to worry: It's a worthy list, one that's well suited to the food. You will have to navigate it yourself, though, I'm afraid — when I asked my waitress for descriptions of a couple of wines one evening, all I got was, “I don't really like those ones.”

It is a peculiar place, servicewise. On the one hand, they come across as preemptively defensive; on the other, you can barely go three minutes without someone checking in on you. There's one busboy who seems to have had the daylights scared out of him by management, so anxious is he to keep busy, clear those plates, fill that water, wipe that table.

All your food may well come at once, which the waiter will insist is just the way you have to deal with it — unless he decides to “course it out” for you, which he offers to do on another night. The mixture of overzealousness and defensive power plays sets quite an odd tone.

But whatever they're doing at Little Sister, it's working. The small room is packed, and reservations are not easy to come by. The one time I attempted to walk in without one, the hostess looked at me as though I had asked her to perform open-heart surgery right there on the sidewalk. (She did manage to squeeze us in, so maybe it's all part of the act.)

See more of Anne Fishbein's photos of Little Sister.

Little Sister has something to teach Manhattan Beach about attitude and loud rap music and bold, very good Southeast Asian small plates — and Manhattan Beach is lapping it up.

Just so you know? I'd wade through a lot worse attitude to get to food this good.

LITTLE SISTER | Three stars | 1131 Manhattan Ave., Manhattan Beach | (310) 545-2096 | littlesistermb.com | Daily, 5 p.m.-late (last reservation at 10 p.m.) | Shared plates, $8-$32 | Beer and wine | Street parking

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