It was 1999, and director Kabir Khan was 25. It was an exciting time, he says, as he readied for the journey of a lifetime. He was setting off on a road trip from Singapore, through Malaysia and Burma, back to India. What made it better was that his co-travellers included, Captain Lakshmi Sahgal and Gurbaksh Singh Dhillon, both aged 86 and former veterans of Subhash Chandra Bose's Indian National Army (INA). Formed in Singapore in 1942, the INA, led by Bose, aimed to march to Delhi and oust the British. Khan admits his obsession with what was locally referred to as the Azad Hind Fauj. "I was just a few years out of film school then and I got the opportunity to travel with them for my documentary, The Forgotten Army. This was the first time since World War II, that they were retracing the route the Fauj had taken. It was also the first time anyone from the INA was going back to Burma. It was special for them. As for me, I was being told the story by those who were part of history," Khan says on the eve of the launch of his Amazon Original show. The five-part series chronicles the story of Lieutenant Sodhi and his army of men and women fighting for Indian independence.

His interest in the Fauj ensured he didn't forget that he had long wanted to turn the documentary into a feature. But he knew, it was an ambitious project. It took him 20 years to recreate it in a fictionalised format. "The story never left me. The reason I don't make sequels is that once I have made a movie, the story is done. With this one, I felt, it needed a larger canvas. It was a promise I had made to Captain Sahgal and Captain Dhillon. When I made the transition to features, this was the first script I wrote. It kept growing inside me, and the research was internalised in the form of this goldmine of information that I had heard from them," says the two-time National Award winner.

Kabir Khan. Pic/ Sayyed Sameer Abedi