New dog had been settling in fine. She was shedding an impossible amount of fur; she was killing tasty woodland creatures in the backyard and leaving them, catlike, at our back door; she’d quit biting the children. She loved nothing more than to spend hours on the deck, paws crossed, surveying her domain. I have pictures of her out there in rain, snow, sleet, and hail. The postal service had nothing on her. And then she learned to climb the chain-link fence.

At first, she was just gone. We’d call for her, looking behind the shed, under the deck, but then here she’d come, streaking down the middle of the street, skidding to a stop at our front door. We’d retrieve her from our neighbors’ yards. The boys grew nervous. We hung a fancy wire system six inches above the fence. That worked for a few months. We hollered at her when she stood on her hind legs. That worked for a few months more. But: boys, dinner, boys, homework, mail, phone, boys, just taking your eyes off her for five seconds so you could top off your coffee — we were living on borrowed time.

Saturday morning. Mid-spring. I’m still asleep, recovering from a nasty chest cold. From downstairs, the sound of grave alarm. The boys come thundering up. Mamá’s already chasing her, they tell me, crying. I throw on my robe over my pajama pants, which are pink-striped, and women’s. I put on a pair of ragged slippers. In the front yard, I meet my neighbor, who points up the hill. Blocks, she tells me. New Dog was after a squirrel. They’re gone.

I catch up to my wife, who is also in tears. We split up. I find the dog about half a mile from home. She turns to look at me over her shoulder, makes eye contact — and doubles down. I chase her into downtown. She crosses a six-lane one-way street, against the light. I’m sure I’m going to see her run over, and I’m running scenarios of how I’ll tell the kids. Somehow, I corner her in a condo complex. I’ve been screaming for half an hour. All the next week, I’ll teach in a whisper. I carry the dog one mile back to the house. My wife meets me at the door. That’s it, she says. We’re getting a trainer.

In ball fields and greenways in Greensboro and outside of Marion and on the way to Wilmington. A playground south of Charlotte. If New Dog is with us, we spread out, hook the 10-foot lead on her collar, and call her back and forth between us, treat-training her to come when called. The trainer took a long look at her and said, She’s a working breed, whatever she is. She needs a job. And it’s true: She counts us when we come home, looks for the boys, puts them each to bed at night. She herds us. And she’s learning: We hold up a treat, say her name in a bright, excited voice, and every now and then, she comes. Other times, we chase her and catch that long, long rope.

The last time I did this — train a dog — I was 23 years old. I had no boys, no spouse, no pink-striped pajama pants. That old dog was the only thing in my life. These days, I’m trying to learn a new dog at the same time as I’m learning everything else — the end of third grade and kindergarten, the end of one kind of childhood, the beginning of a new kind of marriage. Into this mix: this good dog, two years this May. Here she comes padding into the kitchen, even now, wagging and dragging low and asking to be let out into the yard. We put two feet of new fence above the old fence. That’s been working so far.

Later, she’ll paw at the back door, come back in, snuggle up on the sofa with me. I’ll rub her ears, and she’ll shed half a bushel of white fur. I try not to tell her too much about her ghost sister, that first dog she so eerily features. About how that dog saved my life. After all, New Dog has her own work to do. She’s staying inside the fence these days. Listening a little better. Maybe she knows that her job’s larger. She’s got more lives to save than one.