Open for lunch Monday through Friday 11:30 a.m. to 2:30 p.m., for dinner Monday through Saturday 5:30 p.m. to 10:30 p.m., light menu served Monday through Saturday 10:30 p.m. to 1:30 a.m. AE, CB, DC, MC, V. Reservations recommended. Prices: At lunch appetizers $2.50 to $6.50, main courses $5 to $12, desserts $2.50 to $4.75; at dinner appetizers $2.50 to $13, main dishes $10 to $16, desserts $2.50 to $4.75. Full dinner with wine, tax and tip $25 to $35 a person.

My Brother and Me, like many pairs of siblings, is an unfathomable combination. Supper club and pub.

Serious and silly. Sophisticated and naive. Trendy and routine.

The glitter starts at the door, with valet parking and a black-tie greeting. The old ,elan disco has been refurbished into a black patent leather kind of place, with mirrored columns, black-tiled tables at lunch, cloths and crystal ice buckets on the tables at dinner. Early in the evening the enormous bar is packed, and late in the evening dance music draws lingerers to the dance floor. There is an air of fun and of dressing up--and a touch of playacting to it all.

The service has generally been fine (especially when they knew they were serving a restaurant critic); the waiters and waitresses were attentive and knowledgeable about the kitchen. The wine list is designed to be enjoyed; the prices are reasonable and the choices are interesting with emphasis on sparkling wines, quite pleasant ones for a little as $13. (Be careful, however, if you ask your waiter or waitress to recommend a wine. Ours pointed us toward the high end of the list.)

My Brother and Me emphasizes seafood on its menu, though there are a few grilled meats at dinner, and sandwiches at lunch. The seafood swings from oysters with caviar to barbecued swordfish, seafood linguine to tempura to fritto misto. Every trend, from smoked meat to white chocolate ice cream to homemade pasta, is covered.

You can have elegant oysters in puff pastry with beurre blanc and caviar (a lot more caviar if you're a restaurant critic, apparently) or down-home French fried onion rings (wonderful thin and crispy ones). The breads are homemade (though no better than most), as are the pastas, the smoked meats, the pastries and the ice creams.

The pricing system is peculiar. Here, the main dishes cost over 25 percent more in the evening. But some of the salads-- swordfish with roasted peppers, Twenty Twenty Salad--are cheaper at dinner. There are dishes that are good values and others that are overpriced; you will pay K Street prices for both.

So what to eat? First, the smoked fish chowder, creamy and smoky, with chunks of potato and celery and an interesting touch of just-wilted, slightly crunchy spinach; it is a rich and delicious soup. Scallop soup, however, tasted like little more than hot cream with sliced scallops. The Oysters Sydney, those with the beurre blanc and caviar, are very good despite tough pastry, but are not worth $13 if the caviar is skimpy. A better risk is seafood linguine, wiry homemade pasta tossed with fresh tiny clams in the shell, mussels, supple scallops and large plump shrimp, with a very light and fresh tomato basil sauce. Salmon L.G. is heavier than it sounds (the menu says steamed, though mine was grilled) but a lovely blend of flavors: mild and fresh fish on a bed of unctuous, buttery, nearly caramelized cabbage and lots of cracked pepper. Appetizers include raw or steamed shellfish, tempuras (in a batter too heavy and soggy) and sat,s that were good but too sweet.

Several of the main course sauces are also too sweet. The barbecue sauce is more sweet than pungent; it made for a vapid smoked chicken at one lunch. Whole sea bass at dinner was a beauty and cooked just enough, with steamy flesh and crusty skin, but be prepared for the sweetness of its gingery and peppery sauce. There are other excesses: Char-broiled swordfish, for instance, was the nicest of fish steaks and cooked to a smoky and crusty but moist state. But its thyme and garlic beurre blanc burned with raw garlic.

It is flawed cooking, but it is still good cooking. And in some cases, it is outstanding. Loin veal chop was boned and cut thick, saut,eed perfectly and permeated with a buttery flavor, topped with a gentle chive and lemon butter sauce, served with those wiry homemade noodles in a light tomato sauce. Also excellent were the crab cakes, top-quality lump crab meat barely bound and not overseasoned or breaded, so that the crab speaks for itself. The coleslaw needs perking up, but vegetable accompaniments tend to be good, particularly the rice. And while the shoestring potatoes are above reproach, it is the onion rings one should not miss (or French fried cabbage if you like variety in your indulgence).

This is indeed a restaurant for indulgence. If there is one area in which it shines, it is desserts. The cheesecake is now world-class, both creamy and light, and outrageously rich. The pecan pie is no less marvelous, its filling nearly butterscotch and not too sweet, its nut topping crisp, though it deserves a better crust. The one it arrives in is salty and insufficiently flaky. There is also a peanut butter pie, light and airy chiffon with a peanut crunch that is subtle. It could do without its drizzle of raspberry pur,ee, as the thick and moist brownies would be better without their bed of strawberry pur,ee and the ice creams are not enhanced by a heavy and tasteless cookie shell.

Here is a good restaurant with a lot of talent aiming to please. It is stretching too hard to be glamorous, which gives it away as a young and somewhat awkward attempt. My Brother and Me should keep trying, but not too hard. All it lacks is a little mellowing.