For a new, high-end restaurant with a young, unsung chef, Abysse certainly has picked a less-than-obvious location. From the nearest subway station, Gaienmae, the walk takes you down winding backstreets and up a flight of stone steps into the heart of residential Aoyama. Print out a map, open up your GPS or hire a guide — it’s definitely worth the expedition.

Not that the address will be new to Tokyo’s seasoned gastronauts: Abysse has taken over the elegant, comfortable little dining room formerly occupied by Florilege before it decamped to Harajuku. That, however, is a double-edged sword. It means there is already an established and well-heeled customer base who know the space, many of whom live in the area. On the other hand, Florilege is a very hard act to follow.

It is already clear, though, that owner and chef Kotaro Meguro and his front-of-house manager Tatsuhiko Taniguchi are more than up to the task. Despite their tender age — both are still only 29 — they combine the assurance that comes from having worked at high-end restaurants with a youthful enthusiasm that is refreshing in Tokyo’s all-too-serious dining scene.

It also helps that Abysse already has a distinct personality. Both at lunch (five courses; ¥4,500) or dinner (nine courses; ¥9,000), the chef’s special prix-fixe menus contain no meat dishes. Not that Meguro’s recipes are entirely meat-free. He is not shy to draw on the flavor and umami of chicken stock or to add the rich mouthfeel of foie gras to a recipe. But from start to finish, seafood rules.

Meguro learned well from the time he spent in Marseille, working at Le Petit Nice under Michelin three-starred chef Gerald Passedat. But he also has some great dishes of his own. The opening appetizer is a ball resembling takoyaki (octopus dumplings), which is made not with Japanese ingredients (and contains no octopus) but with a deeply savory, almost-molten lobster bisque.

He returns to a similar theme later in the meal with his signature soupe de poisson. Some 10 kinds of fish go into this dark, powerfully concentrated bouillabaisse-type fish soup, along with five spices, including anise, coriander and saffron stigmas as a garnish. On the side, you are served a delicate crispbread, which is spread with garlicky aioli and topped with grated Parmesan — a highly refined take on the standard accompaniments. This is a brilliant dish, rich and resonant of the ocean depths after which Abysse is named. You will want to lap up every last drop.

There are several other memorable moments, such as his seafood version of boudin noir (blood sausage), stuffed not with meat but squid and stained black with squid ink. But the absolute highlight is Meguro’s pairing of foie gras with kegani crab meat, seasoned with konatsu citrus, piled onto a base of flaky pastry and garnished liberally with chives.

As you’d expect, the wine list veers heavily toward whites, although Taniguchi manages to include a couple of light reds in his wine pairings. It all adds up to a highly satisfying whole. And best of all, reservations are still easy to come by. This will inevitably change, as the word gets out.

Robbie Swinnerton blogs at www.tokyofoodfile.com.