Sergeant Craig Grossi was serving in the Marine Corps in a remote part of Afghanistan in 2010 when he came across a stray dog and decided to approach him.

"As soon as I got close to him," the Purple Heart recipient recalls, "he started wagging his little tail."

RELATED: You Have to See these Adorable Puppies!

"He was hot, hungry, covered in bugs and had absolutely no reason to show me any kind of trust or love," Craig continues. "But he did it right away."

Craig named his new furry friend Fred.

Over the next two months, Fred followed Craig wherever he went -- and of course, he stole his heart.

RELATED: Puppy Love! How to Help Your Dog Lose Weight

"When it came for us to leave," the author of the newly released book, "Craig & Fred," recounts, "I said, 'If you follow us, if you try to stick with us -- through all the noise and everything that happens when the helicopter comes -- I’ll take that as a sign.”

Sure enough, when the helicopter arrived, Fred was right on Craig’s heels -- just as he had been the whole two months prior.

Ultimately, while getting Fred to the United States wasn’t the easiest feat for Craig, he remained "stubbornly positive," as he puts it, and made sure it happened.

"It was the hardest and best thing I’ve ever done," he says.

Watch Craig talk more about Fred’s journey home in the video above! (Lucky for us, the adorable duo paid us a visit!)