There's an almost divine duality at Kaia, the latest restaurant from Xenia Greek Hospitality, the hit-making team behind Greek hot spots Bar Vlaha and Krasi, which opens in the South End on Friday, November 22. Seafood from afar, seasonal produce from around the corner. Here, fresh-caught fish and go-with-the flow plates find a home next to dishes dashed with wild sauces that took months to make.

The seafood-laden meze-leaning menu designed by Xenia's culinary director Brendan Pelley and Felipe Goncalves, Kaia's executive chef, features modern interpretations of dishes you'd find in the Greek islands that dot the Aegean Sea. Think, whole-grilled fish and raw preparations of tuna and oysters. The 100-seat, 3,500 square-foot restaurant is a multi-textured fantasy by Panos Efstratiou of the Greece-based firm RFORM (the same firm that designed Xenia's other ventures). From the raw brick to the weathered metal and the giant concrete column by the stately stone bar, Xenia's CEO Demetri Tsolakis likens it to the Aegean Coast's "sun-kissed beach and sunsets, and the vibe of Mykonos."

But for all that sea-like flow, there's also a deeply rooted purpose to the menu at Kaia, a variant name of "Gaia," the Greek Earth mother goddess. A goal of bringing food waste as close to zero as possible ignited in Pelley and Goncalves a wild sense of innovation that uses both ancient cooking methods and modern gadgets. Vegetable scraps juiced and fermented, worked into sauces and butters, with the dehydrated solids used like spices. Fish bones and heads held at a hot temperature in the sous vide for ten days to make sauce -- the bones nearly dissolve in the process until the last bits are strained at the end -- instead of going right to the compost heap. Kaia's approach to zero-waste might seem familiar to "yayas," or grandmothers, on Aegean islands, which are not the most abundant landscapes. As Pelley puts it, "There are no yayas on the islands throwing shit out. Anything edible is getting eaten. Nothing is going to waste."

Diners might be able to breeze in for hyper-seasonal meals on-the-fly (Tsolakis notes a number of seats will be held for walk-ins only, in response to diners having a hard time with reservations all throughout the city), but the opening menu of raw fish (plus one lamb carpaccio dish), whole-grilled fish, and twelve meze stems from a ton of preparation. "We spent the whole summer foraging and gathering any and everything we had," Goncalves says. "We either pickled or fermented it. We capered greens, sea vegetables, anything that Brendan foraged himself or that our team was able to find. Everything was preserved and it's gonna go into the menu at some point. It just became the standard now."

Goncalves was scouted from Menton, which closed early this year, because of his contemporary skills and knowledge of fermentation, dry aging, and butchery. Sous chefs Owen Lovering (Amar, Tasting Counter) and Junyoung Ma (No. 9 Park) also collaborated on the menu. Though, possibly the wildest flavor-boosting and waste-cutting ingredient is the bread amino, found in the dakos bread, beet, and persimmon meze dish, which Goncalves invented. He makes the soy-sauce-like condiment by introducing a house-built koji (a mold used for making things like sake), salt, and liquid to sourdough scraps from Bar Vlaha. The dish also features chips that taste like soy sauce with chocolate, made from dehydrated solids from making the sauce.

Then there's the miso -- a common ingredient in Japanese cuisine, one of a few global influences on the menu. "It takes from one to six months right now for us to develop flavor on the chickpea miso," Goncalves says of the ingredient found in the deceptively humble cabbage dish on the menu, which also features sweet goldenrod and almonds. The menu also features fish sauce -- though it's more familiar in Southeast Asian cuisine, the ancient Greeks likely invented the condiment, called garos -- made from mackerel, "a fish that fishermen use as bait in Boston," Pelley says. Mackerel is also used to make XO sauce, and seasoning flakes, and chips. One product might yield five different ingredients.

That's not to say that the menu is a feast of scraps. Take a look at the fish -- different sizes and types available based on daily catches and imported goodies from Greece -- that are served whole and treated almost like slabs of steak, served with the likes of orange blossom honey and a house lemon and olive oil sauce. Kaia showcases a caviar and truffle program for baller meals, too. Truffles on the opening menu sourced by Mushroom Shop in Somerville were foraged in Burgundy, France. He recommends adding truffle to the umami-forward cod cheeks dish, which also features rock samphire (a plant that grows wild all over the Aegean), and a kind of seaweed-butter risotto.

For the beverage program, wine director Evan Turner sourced wines only from the Aegean. Some bottles on offer at Kaia are only otherwise available in Greece. And leave it to Lou Charbonneau, who just worked his magic on refreshing his cocktail menu at sister spot Hecate, to craft a cocktail menu that reimagines classic drinks as lighter, balanced sips to pare with seafood-focused fare. "Each drink is highlighted by two ingredients, one of them being more Aegean-focused," he says. The fig leaf and oolong highball features Ketel One vodka, quick-steeped oolong tea and fig leaf with some salts, and then whole drink is carbonated. It's a subtle upgrade on a vodka soda. Find an espresso martini upgrade ("I wanted to make it brighter and fruitier and refreshing, and still maintain using Greek ingredients," per Charbonneau) featuring chicory-infused Metaxa Greek brandy, cardamom, and burnt sugar.

"What else can we show from Greece?" Tsolakis says. "There's so much and it doesn't just fit in one concept. It's an educational thing as well when you go to our restaurants." With all that's fermenting at Kaia, and with many more regions to explore (and, hey, around 246 inhabited islands), here's hoping it's a question Xenia keeps answering.