Director Kang Je-gyu, who is behind hit films “Shiri” (1999), “Brotherhood” (2004) and “Take Off,” (2009) is making a comeback after seven years, this time with the real-life story of three legendary marathoners in "Road to Boston."

The film is based on the life story of Son Kee-chung, the 1936 Berlin Olympics marathon gold medalist, and how he trained the Korean team for the first international marathon held after World War II. Ha Jung-woo stars as Son while Yim Si-wan plays another marathoner, Suh Yun-bok, who learns from Son and wins the Boston Marathon in 1947.

“Because the film is about the real life story of three legendary South Korean marathoners, I focused on depicting the realism. While writing the screenplay, I also committed myself to omitting the fictional part to diligently bring real life events to the film,” said director Kang during a press conference held in Lotte Cinema Konkuk University in Seoul on Thursday.

The other thing he has prioritized in making such a “realistic” movie about a marathon has been to portray protagonist Yim Si-wan as real as the actual marathon runner himself. “Road to Boston” was Yim’s first work acting as a runner, although he also played the character of a runner in JTBC drama “Run On,” which aired before the film’s release.

“I’ve been enjoying running as a healthy hobby, but I’ve never actually done it professionally. For the film, I trained for two months and I tried my best to get the physical conditioning of a marathoner and at one point, my body fat went down as low as 6 percent,” said Yim, adding that he would also do a short workout in his spare time on the set to build his muscles as a marathoner.

Prolific actor Ha said that his character, Son, moved him from the moment he read the screenplay.

“It was truly heartbreaking to read the part in which Son had to put a Japanese flag on his uniform and later receives criticism for hiding it with his hands. But he makes a comeback with Suh, an up-and-coming marathoner and the first marathoner to run with Korean flag, as his coach,” said Ha.

“Every single line that Son mentions in the film really touched my heart, which also made me act carefully as he is a person who really existed,” he added.

Although the film wrapped up shooting three years ago in 2020, the theatrical release had been delayed due to the COVID-19 pandemic. Director Kang said that he was actually thankful for the time he could spend continuously editing and editing to produce the final version.

“It was a very harsh and difficult time for me, but to be honest, I completed the final version just two weeks ago, after an endless process of editing. I’m grateful that I was able to attribute such effort to this film to increase the quality,” said Kang.

Regarding the controversy concerning not removing actor Bae Seong-woo -- who was embroiled in a DUI case in 2020 -- from the final version, Kang said deleting Bae's part would not be a way to pay respects to Korea’s legendary marathoners. Bae portrays another marathoner, Nam Seung-ryong, who won the bronze medal in the marathon at the 1936 Summer Olympics alongside gold medalist Son.

After being found guilty of drunk driving, Bae was banned from appearing on major televisions in South Korea and "Road to Boston" marks his return to the silver screen after the controversy.

“I didn't think it would be right to minimize or alter the story due to an incident surrounding an actor who plays him,” Kang told reporters.

“Road to Boston” hits local theaters on Sept. 27.