IF YOU WANT TO MAKE GOD LAUGH," my mother says on the phone, "tell him your plan." It is the third time she's used this line this morning. She is confused. She is nervous. She is scared. The hip replacement surgery is scheduled to happen in about an hour. "I mean, can you believe I'm back here in the body shop?" she says. "They're going to knock me out. So at least I won't have to hear my bones clanking."

"Well, I'll say a prayer for you," I say.

"Thanks," she says. "And tell God I got the point."

"All right."

"If you want to make God laugh . . . "

"Right."

The plan in this case was the one she made to come visit me for the weekend. Nothing extraordinary about that except my mother has not been able to travel for well over a year because of a strange disease she contracted, Guillain-Barre syndrome, which temporarily paralyzed most of her body. She spent months last year in the hospital, then months in rehab, then months at home relearning how to do just about everything. Nearing full recovery, she was finally able to drive, shop, visit her friends. She felt that she had her life back. She planned her trip to visit me. She was so excited. It was as if she were taking a trip around the world. She got a new suitcase. She got a manicure, a new outfit. She had her eyebrows waxed for the first time in her life.

And then just two days before the trip, she tripped. Those darn rubber soles. She went tumbling to the ground, heard the crack. Her hip, she had broken her hip. When the ambulance came, she cried, wailed like a baby. "I'm not crying because of my hip!" she said to the driver. "I'm just so disappointed. I was going to visit my daughter."

The operation goes off without a hitch. Two days later, they move my mom to the rehab hospital, which is where I join her.

It feels awful to be back here again. These same long halls. This same sour smell. These same shiny floor tiles. That same cafeteria; they haven't changed the schedule of daily specials since last year. I know this place too well. And I don't know it half as well as my mother knows it. I wonder if this setback is going to do her in. How many times can a person go backward?

Room 111. I see her sitting there, in her electric wheelchair, the same one she used last year.

"You're here!" she says, flashing a grin. "Look at me!" She opens her arms wide. "Don't I look great!"

"Well, yeah," I say. "But . . . " I was expecting a little misery. A little whining or something.

"But look at my eyebrows," she says. "Did I tell you I got them waxed? Don't I look like I'm in a constant state of surprise?"

"Not really."

"Well, I guess I am in a state of surprise. Because I'm doing great. Coming back to this place, I just realize how lucky I am."

Lucky? To be back in a wheelchair? To have to learn how to walk yet again? Lucky?

"Mom, do they have you on some very good drugs or something?"

"I am such a different person," she says. "When I came here last year, I was so depressed, so impatient. Now look at me. I have this . . . serenity. This is what I've learned. I am not in charge. I surrendered. Surrender and serenity. I never realized how close those two words are. Think about that!"

"Okay."

"You want to go get one of those soft pretzels in the cafeteria?" she asks. "They still have them."

She throws her wheelchair into fast forward, spins around and goes zooming down the hall. I ask her to please slow down. I can't walk that fast. Plus, I'm afraid she's going to knock someone over. She does not slow down. She laughs. "Aren't we having a great time?" she says.

"We are," I say.

"I'm so glad you're having a daughter," she says, referring to the baby girl from China I'm hoping to adopt in a few months. "Daughters can be such great friends. Aren't we great friends?"

"We are," I say, imagining myself at 75, in a rehab hospital with a brand-new hip. Will I be cheerful, optimistic, philosophical? Will I be strong enough to turn disappointment into an adventure? I wonder if this is mothering at its best, and where I sign up for lessons.

We head outside to eat our pretzels and my mother wants a better look at some purple wildflowers, so we wander off the pavement. But this is not an all-terrain wheelchair, and so of course she gets stuck in the mud. The wheels spin and spin and we laugh and laugh in the crisp autumn air, laugh as if it's the funniest thing that has happened since that trip to San Francisco years ago, just the two of us, hopelessly lost in the thickest fog.

Jeanne Marie Laskas's e-mail address is laskasmail@aol.com.