by Micah Flores — Photographed by Matt Baldelli & Jazz Martin

Enter the unassuming world of 150 Kneeland Street in the heart of Boston’s Leather District and prepare to experience a scene not typical of the city.

The door opens and guests are immediately drawn in. Water trickles down a sleek glass wall to the left. Hostesses greet you among glistening champagne bottles.

Up ahead lies the party and those who make it happen. There is mingling at the bar, and many guests lounge all around the surrounding low-slung leather seating.

It is early evening on Wednesday, September 9, and the fourth and final private opening party at Splash – a new Vegas-inspired ultra lounge, complete with a gourmet burger and tapas bar – is already on the verge of going off.

Later on in the evening, however, Splash will officially open for business to the general, well dressed, public. But in the meantime, the invited guests steadily multiply. Most sip an array of complimentary spirits from the bar. But everyone feasts on a steady stream of delicious tapas and miniature burger bar offerings, or sliders, which are being passed off the trays of the generous service staff.

The tapas are unbelievable.

The bacon-wrapped U10 sea scallops are succulent, flavorful and fresh. There is no way to stop at just one. The same goes for the bay oysters with limoncello sorbet, which, by the way, are even better than they sound. The Ahi Tuna Tartare served on faro crackers, feature a perfect mingling of tender fresh tuna and flaky crust. But it is the chilled chunks of Alaskan king crab leg meat — still sitting in its tapas-sized section of a shell — that makes me think: now would be a fine time to die.

Gratuitous feasting aside: a survey of guests gathered on this evening reveals that most hail from varied walks of Bostonian life. From finance, even biotechnology, to the service industry and beyond, Splash seems to be catering to a sophisticated “leave-your-pretentiousness-at-the-door,” as one guest puts it, kind of gathering.

Frank Quaratiello, the Boston Herald’s deputy business editor, and Larry Meehan, the director of public relations and tourism for the Greater Boston Convention and Visitor’s Bureau – are representative of some of the news and public relations gurus randomly strewn about the mix. No matter their trade, those in attendance take well to the scene; clearly leaving their middle-of-the-week worries far behind.

One thing everyone on hand has in common is that they are all guests of owner Frank DePasquale, the North End restaurateur whose vision for Splash is (besides the complimentary alcoholic beverages) the main buzz throughout this newly renovated venue.

Scotty Tyler, a concierge from the Nine Zero Hotel, located at 90 Tremont Street, takes time to comment that there are clearly no other venues like Splash in this city.

“Everything that Frank DePasquale touches turns to gold,” the 28-year-old says, pausing to enjoy one of Splash’s famous steak tips. “He just has an eye.”

“They’re the most popular in the house,” the waitress holding the tray of tender tips says before enticing other nearby gatherers.

DePasquale’s eye for superior food and ambiance is a phenomenon that is not unique to just Splash.

His hottest restaurants include well-known North End favorites like Bricco, Mare and Trattoria Il Panino. He also owns the financial district’s Umbria Prime, which offers the better of two very different worlds: a fine dining steak house and nightclub.

“From the staff to the service in his restaurants,” Tyler adds, “It all speaks for itself.”

On the opposite side of the bar, DePasquale sits on a stool and tells of his inspiration for Splash, and how it “veered slightly” from the Italian concept theme for which he has been known to master.

“I came back from a vacation, and said ‘why don’t we have something like this in Boston,’” DePasquale recalls of a previous trip to Vegas. “I like to continue the party.”

With this, his latest venture, DePasquale says he is looking to connect with a well dressed, 25-plus clientele.

By the looks of his guests on this night, that target group is indeed represented.

Sipping on a signature pear margarita and taking time out to enjoy a magnificent skewer of Chilean sea bass back on the other side of the bar is equity analyst Bora Kem. “This is the best drink I’ve had tonight,” he says, adding that that his first impression upon entering the venue was that it “was very truly, a hip place.”

“It’s very unique and the crowd is electric,” Kem says of those filing in around him. Jonathan Gabriel, a 25-year-old hovering alongside Kem, says Splash’s water theme was reminiscent of the Detox Pool Party at the Palms Casino Resort in Las Vegas.

“I’ll be interested in seeing what kind of scene materializes here,” he says, pausing to saver not one but two of mom’s homemade meatballs. “Upstairs is like Vegas or LA with the bottle service and the pool tables.”

Another guest, Chris Angers of Quincy, says after finishing his draft Peroni that Splash far exceeds his critical eye.

“It appears to be an ultra nice night club that still has a relaxed feel to it, says Angers, mentioning that he has worked as a manager for several other Boston night clubs — including Jillians and Felt.

Angers also cannot help but notice how the bartenders at Splash seem to be mixing and shaking authentic cocktails.

“They’re muddling their own mint for mojitos. That does not happen a lot,” he says, motioning toward the ladies doing their thing behind the bar.

But the most unique part of the club, says Angers, echoing comments said by others, is the luxury roof deck up top.

A trip up two side sets of stairs, past rooms with ultra modern-looking pool tables and intimate sidebars, reveals much of the fuss.

Well over 100 guests mix under the cool evening air. Some relax under the cover of plush cabanas lining the rooftop space; others sit atop the queen-sized beds. Besides the patio bar turning out quality cocktails, another highlight of the rooftop patio is its decorative water fountain, further emphasizing the sleek and fluid theme of water.

Patricia Roketenetz, a wealth management representative who works downtown, stands huddled over a cocktail table with friend Judith Herrick, a concierge with Boston’s Four Seasons Condominiums.

“There’s definitely a nice kind of Vegas, Miami feel up here,” Roketenetz says in between sips of bubbly Prosecco with cherries. “I like the casual, upscale feel. You can have a mix.”

As both ladies agree that their clients would be impressed by what Splash has to offer, their friend, Tom Gorman of Cohasset Harbor Resort, enters the picture.

“You sink your teeth into this,” says Gorman, raising up a tender lamb lollypop with his hand, “and you know you got something good.”

Gorman says as a concierge, it is especially important to try the food and experience the scene before recommending it to his guests.

“It gives me more credibility,” he says.

At another cocktail table stands Jon Liebtag, a finance manager and his friend Kip Cross, who works in corporate communications.

Cross, sipping on a Chivas on the rocks, says that he had found out about the night’s private party from a promotion notification on the UrbanDaddy website.

“They sent me an e-mail and I sent them a Twitter message explaining why I thought I should come,” the 29-year-old says as the wait staff continues to offer yet more unique offerings, like the Black Angus sliders.

“The wait staff has been really nice and the food tastes great,” he says.

But don’t take their word for it. Come stag like me, meet up with friends or book a private room for your special event or intimate gathering.

Splash is now open for business Wednesday through Saturday from 5 p.m. to 2 a.m. Call (617) 426-6397 or visit www.splash150kneeland.com for more information or to make a splash of your own.