When Guy Partnerman and Lady Millionaire purchased a brownstone in the most Brooklyn-themed neighborhood of Brooklyn, there was only one drawback: the home was too beautiful.

“Crown-molded ceilings, natural sunlight, not a trace of ‘Live, Laugh, Love’ decor. To call it a fixer-upper wouldn’t be right, but we had some ideas. That’s who we are. People with ideas and the means to execute them flawlessly,” said Ms. Millionaire, 37, a movement-based flautist.

“We couldn’t just raze the thing in the grand tradition of the heathens we pretend not to be,” added Mr. Partnerman, 69. “There were ordinances.”

Thanks to privilege, the couple moved quickly on an offer, an eye-watering sum that makes you feel karmically flawed. They inspected the home with their clear-frame glasses and unisex workwear. Mr. Partnerman, a commodities trader specializing in shorting pork futures, is a sustainable design buff. He realized he could rip up the floorboards, cabinets, walls, and every historical detail, replacing them with Amazonian timber salvaged from impending wildfires.

The couple worked with Johanna McVisionary of Members FDIC, an architecture firm that doesn’t typically work in the residential space.

“I told Guy that his jawbone looked sharp enough to chisel into the foundation, since they wanted to dig a custom grotto with a marble freshwater pool. We broke ground on day one,” said Ms. McVisionary. “The three of us made love after each permit passed, with no complaints from the board and zero hostility from the neighbors, many of whom were impressed by our wind-powered jackhammers.”

Midst the renovation, the couple had twin girls. They already had children, but now they have more children. Gaze upon the picture of their adorable family. They are charming. You hate them, and you also want to become them.

“I told Lady, ‘Now we really have to childproof the place,’” said Mr. Partnerman.

“I wish to add something self-deprecating, but I’m finding it exhausting,” added Ms. Millionaire.

Ms. McVisionary installed his-and-hers front doors, a walk-in veggie crisper, multiple tax shelters, and a CBD-infused HVAC system. The chairs are works of art, and the works of art are chair-focused. The bathroom tile is by Supreme.

Renovations were going to plan until Ms. McVisionary discovered, in the sub-basement, a purple Bonsai tree glittering with fairy dust. The very spot where they were going to install a wet bar. A bargain was struck with the Bonsai. Instead of uprooting it, they wrapped the bar around the tree, crafted with wood from the Ark of the Covenant. In return, the Bonsai granted the family a tax abatement that would extend for five generations.

As for the kids’ rooms, they now resemble museum dioramas representing ideal notions of childhood, with bespoke toys that no regular child would touch. In a final flourish, Ms. McVisionary excavated skeletons in the family’s closet and reclaimed the bones, creating ossified inlays. For the kitchen, the couple did make one concession. The room was designed around an antique Italian toaster oven that once belonged to Maria Montessori, a housewarming gift from Mr. Partnerman’s parents, who still bear presents from the afterlife.

“We learn from it,” said Ms. Millionaire. “And it makes the most resonant ding.”

In total, the renovation cost you your otherwise fine weekend mood.

Since the project wrapped, the brownstone has become more of a pied-à-terre, as Mr. Partnerman accepted a job at a Latvian tech startup. Nevertheless, the home’s industrial-chic floors see a lot of tread. The twins, Flax and Kayden, have found ample room to play with their sister, Harrisburg, 17, as well as the children from Mr. Partnerman’s previous marriages, Skip, 2, Raimund, 39, and Royal, 5. Ms. Millionaire’s third husband occasionally stays when the family isn’t in town.

“The work is never done,” she said recently. “But before the city succumbs to flooding and famine in a few decades, we wanted a place that feels like home.”