Director Nikhil Advani and his team spent almost two years researching for his upcoming film, D-Day. Every aspect of the principal characters —their background, looks, dress and body language — was looked into, in detail.

The contemporary action drama stars Rishi Kapoor, Irrfan, Arjun Rampal, Huma Qureshi, Shruti Haasan, Akash Dahiya, Nassar, Chandan Roy Sanyal and Shriswara in pivotal roles.

Once Nikhil got the basic idea — of getting an underworld don back from across the border — the filmmaker and his writers, Ritesh Shah and Suresh Nair, developed the story and screenplay.

"We looked up all possible information on the Internet. Details like the names of roads in Karachi, and how one can infiltrate India through Kashmir, the Rann of Kutch, Nepal, Rajasthan and Punjab, were looked into," says the director.

Equally important was characterisation. Says Nikhil, "Irrfan's character is someone who has stayed in Karachi for 10 years. So, we had to get all the details, of a person living abroad under a false identity, right. It was also important to get the right actress to play his wife. We auditioned actresses from Iran and Iraq, because we wanted someone without an image. That's how we found Shriswara."

For Arjun's character, who is a member of the special forces unit of the Research and Analysis Wing (RAW), the team also studied RAW's recruitment process. "We met some former chiefs of the organisation who came on board as consultants once the script was complete," says the filmmaker.

Locations played an equally important role. "Our team took us to places in Ahmedabad where the script came alive," says Nikhil, adding that they paid as much attention to the music. "Our film is an action thriller. Normally, a song might break the pace of such a film, but we ensured that the music took the story ahead," he says. The film is co-produced by Essel Vision Productions.

D-Day, produced by DAR Motion Pictures and Emmay Entertainment, releases July 19. — TOI