It was going to be the perfect rehearsal dinner.

The mother of the groom had spent six months fine-tuning the menu, choosing a feast for 88 that included salmon and chocolate mousse in the stately banquet room of Davio's restaurant. The flowers - yellow and orange Gerbera daisies growing in tins of grass - were neatly accented by tablecloths with a sheer daisy-patterned overlay. The four-piece jazz ensemble was plugged in and ready to entertain the guests who would gather for the 7 p.m. event.

And then the lights went out.

Wacky movie premise? No, just another bump in the road in the restaurant and party-planning world.

On a Friday afternoon earlier this month, Davio's was one of 25 Center City buildings that lost power at about 4:45 p.m. Chef David Boyle and his staff had experienced such outages before, albeit not one so close to the dinner hour. They checked with Peco, called their building management, and waited.

"As the minutes went by, we were praying," Boyle said. "We were trying to wait until the last minute to change the venue."

Most of the food - the cold appetizers, the crudités - was ready to go. The entrées were prepped. The tables were set. The extra banquet staff was on hand.

The power came back on at a nearby store. Davio's remained dark. At 5:30 p.m., the restaurant sent out an SOS to the event's planner, Lynne Brownstein, co-owner of West Conshohocken's Arrangements Unlimited.

Brownstein, who has been in the event-planning business for more than 30 years, said she always was ready to handle minor emergencies, such as when the bride lost her bouquet before she was due to walk down the aisle. She's even tackled major snafus, such as when she planned a wedding for one of Robert Kennedy's sons and a truck carrying watermelons jackknifed on the highway, blocking the road with fruit and trapping the wedding party in cars behind it. ("That was really a mess," she said.)

But the power outage was a new challenge. When she called other Center City restaurants looking for instant seating for 88, they thought she was joking. She considered running to an upscale grocery store for ready-made dishes.

"I think it took 100 years off my life," she said. "You pray, but you can't stop what you're doing while you're praying."

She found space - and aid - at the Westin Hotel, the same facility that was to host the wedding the next day.

The Westin's banquet room was unusable, as it was already set for the nuptials.

Westin general manager Mike Manzari said he looked at the team around him and never panicked.

"Everybody else was calm and I knew it was going to happen with form and fashion," Manzari said. "They had a can-do attitude."

The solution: Serve cocktails in the lobby and transform the area outside the banquet room into a dining area. Of course, that meant transferring the flowers and decorations from Davio's via bell carts, wheeling them about a block and across 17th Street.

Davio's banquet area is on the 13th floor, the penthouse of the building the restaurant is in. And it was dark in the room as staff tried to break it down to retrieve the tablecloths and centerpieces, but at least the elevator was running by generator.

"It definitely looked like a procession of some sort," Boyle said, "with all the waiters in their white jackets and all the carts." Flowers and votive candles were teetering as the carts were raced to the Westin.

In the end, "It pretty much went off without a hitch," Boyle said, apparently forgetting the whole power-outage drama.

At the Westin, the tables were quickly reassembled and the Westin chefs were given a copy of the menu. They used Davio's appetizers while preparing their own entrees. Manzari said the kitchen had plenty of salmon and chicken on hand, as well as other items for the rest of the menu: herb risotto, asparagus, and Swiss chard. All they really needed were the guests and the table decor.

Manzari called in extra help - a woman who was on her way to a Phillies game; a man who was driving to visit his daughter in Delaware; a couple who were taking a walk with their daughter, who was then set up on a hotel computer while her parents worked.

"It makes you glad you work with a team," Manzari said.

The power came back on at Davio's around 7:45 p.m. Boyle said the staff had helped about half of those with dinner reservations find other restaurants to enjoy that night.

"Our bottom line was that the guests were happy," Boyle said.

Both families were happy, Brownstein said. The rehearsal dinner was a great success. The wedding went off without a problem.

"I nearly died in the process," said Brownstein. "But it was beautiful."