– Grace Bunke, 14, leapt into Lake Lanier under blue skies and cotton-white clouds. She seemed to glide across the shimmering water, making a 1-mile swim look so easy. But every stroke in the water propelling Grace forward during the swim last year was a grueling challenge, and testament to the teenager’s extraordinary strength and determination.

Just a few years earlier, Grace, a girl with pale blue eyes, a warm smile and an infectious laugh, started swimming competitively at age 12 — after undergoing treatment for a type of bone cancer called osteosarcoma. She swam faster over the years, even after relapsing, even after the cancer had spread into her lungs and spine. She completed the Lake Lanier swim, a 2017 Swim Across America charity event that raises money for cancer research, in 27 minutes — a solid time for any strong swimmer.

Three months after the swim, Grace was hospitalized at Children’s Healthcare of Atlanta. One evening in her hospital room, with the movie “Wonder Woman” on the TV, Grace asked her mom, Vicki Bunke, to help create a fundraising page for the 2018 Swim Across America event, still seven months away.

Connected to IVs for fluids and pain management, Grace turned down the volume of the TV.

Mom, promise you will swim the 1-mile in my place. You may not see me, but I will be there.

Grace died on March 25, one day shy of her 15th birthday. Bunke knew she needed to honor her promise. But it wouldn’t be easy. Bunke had never swum a single lap. She didn’t even like getting in the water. But she would train and swim for Grace. She would be joined by Grace’s oncologist, Dr. Karen Wasilewski-Masker, who also didn’t consider herself a swimmer. They always knew that swimming held a deeper meaning for Grace, with the water offering a place of solace. They would soon find swimming would bring them comfort, too, and connect them to Grace.

Nervous about swimming a long distance, Bunke tried to figure out a way to swim without putting her face all the way in the water. She wore a diving mask to her first swim practice in June. She quickly ditched the diving mask for nose plugs.

From 5:15 to 6:30 a.m. every Monday, Wednesday and Friday, Bunke, 49, and Wasilewski-Masker, 45, trained at Swim Atlanta in east Cobb, the same pool where Grace trained. They started on a summer morning before dawn and completed about 10 laps. Little by little, they added more laps, swimming mostly freestyle with breast stroke breaks along the way.

They were coached by Grace’s coach, Pat Eddy.

Wasilewski-Masker cared for Grace for several months throughout her initial cancer treatment. In late 2016, after Grace’s first relapse, Wasilewski-Masker became the medical director for AFLAC Cancer and Blood Disorders Center, and turned over Grace’s care to another oncologist, at least officially. Wasilewski-Masker remained actively involved in Grace’s care, visiting Grace often and making herself available around the clock to Grace and her family for questions or concerns regarding Grace’s symptoms or pain management.

At the end of Grace’s life, Wasilewski-Masker drove to the hospital at 3 a.m. to help the medical team ease Grace’s pain and make her comfortable. She said she wanted to swim to challenge herself and to honor Grace.

“Last year, Grace swam a mile in the open water of Lake Lanier despite having progressive osteosarcoma throughout her lungs and the bones in her spine,” said Wasilewski-Masker. “I realized if Grace could do that, I needed to suck it up and do this.”

Bunke, who is a school psychologist for Cobb County Schools, and Wasilewski-Masker ground through the first month of practices. Bunke tilted her head up to a white ceiling at Swim Atlanta to help push herself.

As the weeks progressed, Bunke and Wasilewski-Masker moved in the water with more ease, gradually building up their endurance to 44 laps. They swam together, always in lane 6. Days before Swim Across America, they learned they swam in the same lane where Grace practiced.

With her heart racing, Bunke plunged into Lake Lanier on a late September morning. It was sunny, the blue sky punctuated with puffy clouds. With Wasilewski-Masker by her side, Bunke looked up to the sky and thought about Grace.

Bunke and Wasilewski-Masker didn’t rush the swim, alternating between freestyle and breast strokes.

Grace’s sister, Caroline, and a group of friends swam, too, in identical red-white-and-blue starred swimsuits (the same designed suit Grace wore in last year’s swim). One of Grace’s nurse practitioners swam. Coach Pat swam. Dozens of others swam for Grace. The shoreline was dotted with people of all ages wearing red and blue T-shirts with the hashtag AmazingGrace.

As Bunke and Wasilewski-Masker inched their way toward a green buoy that marked a turnaround point, Bunke noticed a motorboat following alongside them. Hanging from its canopy was a red umbrella with the words Amazing Grace written in white.

“Just follow the red umbrella,” said Bunke, noting that Grace became the No. 1 fundraiser for Swim Across America, raising $119,222.

“Grace is leading the way.”