After raising four kids over the last 21 years, Shawn and Rita Yardley were just beginning to prepare for the end of their parenting lives.

They had been thinking they might sell their roomy house in Bangor and buy something a little smaller in anticipation of the day when their kids would all be gone. They had been considering, too, how well they would adapt to being just a couple again after all these years, and what they might have in common with each other when they became empty nesters.

Yet just when they thought they had at least a vague notion of what the future might bring, Shawn Yardley one day caught a glimpse of three beautiful little faces that would turn all those plans upside down.

Suddenly, their role as parents was no longer nearing its natural conclusion but beginning all over again.

In the last two weeks, the Yardleys have attended the graduation of their 21-year-old son, Josh, from the Massachusetts Institute of Technology, and registered Kira, one of the three new additions to the family, in kindergarten classes.

“Yeah, we’re doing it all again,” said Yardley, the 46-year-old director of the Old Town-based River Coalition, an organization of local residents working to improve the lives of children and families in the area. “The whole idea of adopting three kids came right out of the blue, and we truly feel blessed. It was meant to be.”

The family-expansion project began last October when Yardley, a social worker by profession, was browsing through a newsletter from Adoptive and Foster Families of Maine. In it was a photo of the three sisters – 7-year-old Kiana, 5-year-old Kira and 4-year-old Tessa – who were living with two different foster families in southern Maine. The Department of Human Services was looking for a family to adopt the girls and reunite them.

“They wanted an experienced family, with no young children at home,” Yardley said as dark-haired Kira appeared in the kitchen to ask her father for a sandwich. “It’s going to sound corny, I know, but that picture spoke to me somehow. So I stuffed it in my work bag and took it home.”

In front of the TV that Columbus Day weekend, Yardley showed the newsletter to his wife and told her he thought God was sending them a message. Megan, the Yardleys’ 16-year-old daughter, also read the article that night and instantly agreed.

“We’re gonna do this, aren’t we?” she asked her parents, who then reminded her that turning a four-child family into seven was a huge undertaking.

“But we’re the perfect family for them,” Megan insisted. “They aren’t going to find one better.”

After thinking it over for a few days, Yardley called the girls’ caseworker to get the home-study process under way.

“We wanted to make a decision by Thanksgiving,” Yardley recalled. “But I was already thinking of them as our children, and we hadn’t even seen the girls yet. The whole time I’d wake up every morning knowing God wanted me to do this, but why?”

With the home study nearly complete, the Yardleys drove south to the DHS office to visit with all of the people in the girls’ lives – foster parents, caseworkers, therapists. The girls played together in a room, while the Yardleys watched them longingly through a window, aching to hold them.

Around the Christmas holidays, the girls got a chance to visit the Yardley home, which they had seen only on videotape. All the kids were there – Josh, Megan, 19-year-old Jeremy, who is studying biophysics at Brown University and his twin, Shane, a secondary-education major at the University of Maine.

“Then on Jan. 16, the girls came to be with us forever,” Yardley said.

Now, every day reveals something more about these children, their very own children, whom the Yardleys didn’t even know existed a year ago. What kind of toys does each girl like, and what bedtime books do they enjoy? Who eats peanut butter and who hates it? Do they like to play sports? Are they artistic? Are any of them afraid of water, or animals, or being alone at night?

At this point, the oldest girl prefers not to talk about her life before the Yardleys, and the younger ones have few memories to relate.

“Everything about them is new to us,” Yardley said. “Their moods, personalities, likes and dislikes. We don’t know how they’ll respond to situations, not knowing them from birth and watching them grow as we did with our first four kids. It’s all a process of discovery.”

Friends, family and neighbors have been an enormous help, constantly replenishing the inventory of kiddie things that the Yardleys thought they were finished with long ago. Rita, a 44-year-old education technician at Abraham Lincoln School, might come home from work one day, for instance, to find a swing set or a few toys sitting on the porch. People drop off clothing their children have outgrown or send items in the mail that they thought the girls would like.

“I’m really amazed at how quickly we’ve gotten back into the swing of things again,” he said. “It does make me a little uncomfortable, though, when people keep telling us how lucky the girls are to be a part of our family. To tell you the truth, we’re the ones who feel lucky. They have changed us, too.”

Yardley laughs now to consider that he became a proud first-time father at 25, and will be 60 when his last child graduates from high school. He shrugs off the additional financial burdens ahead, though, confident that he and his wife will get by somehow, as humbly and happily as they have for the last 21 years.

Yardley has always felt fortunate, indeed, on Father’s Day. This June 20, he expects to feel at least three times richer.