Saint John's Tavern Oyster House & Raw Bar is a welcoming, second-floor space devoted to briny bivalves and other treasures of the sea.

Its backstory begins a few years ago, when prolific local restaurateur Brian Donnelly began his silent occupation of the corner at Adelaide and John.

What began with Melrose on Adelaide, soon continued with Piccolo Café e Vino, Paradise Grotto, then Saint John's Tavern.

At Saint John's Tavern, the plan was always to begin from the bottom up. A proper English pub on the first floor — with full English breakfasts, pints of ale, and Premier League footie on the telly — Saint John's has grown to include a seafood-centric upstairs.

In time, says co-owner and director Phil Allain, the team plans to open an event space on the third floor.

For now, it's the Oyster House & Raw Bar that's enticing regulars to venture beyond the first floor.

Similar in feel to the pub, the space reveals a comparable inclination toward earthy brick and wood-based décor.

It's the profusion of candlelight and relative lack of big-screen TVs (though there are still a few, reserved for can't-miss sporting events) that perhaps make it sexier and more appropriate for cozy tête-à-têtes.

"We don't want it to be fancier up here," explains Allain, "just maybe a little bit more relaxed and intimate."

Still, at its core this is still a sibling spot to Saint John's Tavern. It's a place that marries caviar, East Coast lobsters and platters of fresh-shucked oysters with the diligent clatter from an open satellite kitchen, approachable price tags and the type of casual, warm service that makes every guest feel like a regular.

Pop in for the team's daily buck-a-shuck promo (from 4-6 p.m.), and you'll be a regular before you know it. Paired with Tabasco, horseradish and tangy mignonette, the day's oyster selection (market price at other times) varies but can include Malpeque, Kumamoto, Kusshi, and more.

From there, peruse group beverage manager Ammar Karam's drink list for the perfect pairing.

Fancy a chilled bottle of Veuve ($175)? An easy-drinking session lager? A dry Martini ($16)? French 75 ($16)? Or, perhaps, The Grand ($23) — a Caesar garnished with another oyster, a plump shrimp and a crab claw? Any path you choose, you'll find your match among the classic options.

Despite the appeal of buck-a-shuck, there's more to the Oyster House & Raw Bar than meaty mollusks. Divided between hot, cold, and towering, the tidy list includes seafood in all its states — from pristine and raw, to marinated, and even charred.

Why seafood? "It was something that the block doesn't have," explains Allain. "Also, our whole goal for everything on the corner is approachable for everyone. … We're trying to be able to offer an experience that some people might think is out of their price range."

A must-have starter, Cheddar Biscuits ($12) come with a complimentary rush of nostalgia for anyone who grew up binging on Red Lobster's. Warm and tender, with a crunchy outer shell and a molten side of garlic butter, these foreshadow good things to come.

Built on a crisp bed of rice, Tuna Tartare ($18) is flavoured with sesame, spicy mayo, togarashi and jalapeño slices. Just the right amount of peppery, these are an easy appie to pop into your mouth as you size up your date.

Also from the "cold" side of the menu, the team's Lobster Roll ($26) is as simple as it should be — and as delicious. Treated lightly with a slick of mayo and sprinkling of chives, East Coast lobster is piled high onto a warm, buttered bun. A team that gets to play with stellar ingredients, this one also knows how to show them off in the best light.

Respect is also evident in the team's dedication to zero-waste cooking. Not always possible, it's a lofty goal that here has some tempting results. Feature Pasta (market price) gives the team a chance to use ingredients destined for an otherwise more tragic fate.

Chunky and rich, with olive oil, capers, tomatoes, a hit of crushed pepper and anchovies, the Puttanesca ($26) served the day we ate there is warming, hearty, and as good an argument for kitchen creativity as any.

A dish meant to feel luxurious yet approachable, Saint John's Tower ($250) is a feast presented vertically. Order one and you'll spend the night nibbling at delicious things, licking your fingers, and, basically, having a kick-ass time.

Tier one is packed with marinated mussels escabeche (along with the toastiest toast ever seen), oysters, Manila clams, tiger shrimp, and snow crab claws. Move up, and discover half of a steamed crab, half of a sizeable lobster and a pot of that essential garlic butter.

Too much for one tower to carry, the 30-gram tin of caviar (also available à la carte, for $75) is served alongside.

It arrives with a host of traditional garnishes — including minced shallot and chives, finely chopped egg whites and yolks and crème fraiche — along with water crackers and plain chips with which to hastily deliver it to one's mouth.

Saint John’s Tavern Oyster House & Raw Bar is located at 117 John Street.