After initial plaudits that came his way, Luka Modric's career at the Bernabéu seems to be off to a rocky start. He remained on the bench in the Champions League match at Ajax on Wednesday and is by no means certain to play in Sunday's Clásico. But if Modric's personal history is anything to go by, the former Tottenham Hotspur creative force can overcome any obstacle and become one of the leading stars at Real Madrid. He's been through hell more than once in his life, coming back stronger each time.

Last month, a Spanish TV crew travelled to coastal Croatia to find "the origins" of Modric and to film this short documentary. They talked to his one-time coaches, former team mates from NK Zadar's youth ranks, friends of the family and journalists. Modric's father, Stipe, didn't take part, saying the nature of his job with the Croatian army requires him to keep a low public profile, but he did OK the project. It's a classic rags-to-riches tale, but also an emotional roller-coaster which does justice to the fact that Modric making it this far is nothing short of a miracle.

There is an abandoned and dilapidated building complex around 60km from the town of Zadar, signposted the "Obrovac Free Zone". It was supposed to be an industrial area and attract investors to this particularly remote and rural part of the country, but no one was ever attracted to it and it was never quite finished.

Next to it is the village of Modrici (plural for Modric), where the Real player's family lived. Further up the narrow and winding road that goes up the Velebit mountain range – one of only two pathways which connected the north and south of Croatia before the modern motorway was built in the last decade – there is a lone house on the curve where Modric spent most of his early childhood. This is where his grandfather, after whom he was named, used to live.

Two decades ago, this was the scene of gruesome war crimes and there are still signs all around indicating the surroundings are not yet cleared of landmines. As Croatia declared its independence, local Serbs captured the area with the help of the Yugoslav army and nationalist volunteers from Serbia, trying to cut off communication and transport between the two parts of the country. On 18 December 1991, Luka Modric senior went up the hill with his cattle. He was murdered in cold blood.

Luka Modric the footballer was only six at the time. As the rest of his family escaped death threats and settled as refugees in one of Zadar's large hotels, he couldn't have conceived the horrors which were happening all around him.

"There was this boy who used to kick the ball around the hotel parking lot all day," says NK Zadar's chairman, Josip Bajlo. "He was skinny and really small for his age, but you could see right away that he had that something special in him. However, none of us could have dreamed that one day he would grow to become the player he is now."

"We were always afraid, that's what I remember the most," says Tomislav Basic, one of Modric's early coaches at NK Zadar. "Thousands of grenades, fired from the surrounding hills, fell on the training pitch in those years, and we were always racing to reach the shelter. Football was our escape from reality."

Basic is sometimes credited as Modric's second father, because he guided the player through some of the toughest football challenges of his teenage years. He took him under his wing after he was rejected by Hajduk Split – the club he supported as a kid, on the grounds of him being too small and fragile. Modric was so disappointed that he contemplated quitting football altogether, but later made his name playing for their bitter rivals Dinamo Zagreb – a recurring pattern, as he confessed his love for both Chelsea and Barcelona at some point in his career, only to end up playing for rival clubs.

Last year, a story broke that his refugee family were so poor they couldn't afford to buy him shinpads, so his father made him some out of small pieces of wood. Modric, however, later denied those claims, saying his first pair of shinpads "had a picture of [Brazil's] Ronaldo on them".

Modric probably did have a proper pair of shinpads, but his family certainly made significant sacrifices to support his footballing dreams. When the war ended and the local authorities enabled them to get back to their village, they chose to move to another refugee hotel in Zadar and live in two small rooms, to support him in following his dreams.

"Luka should never be ashamed of his humble beginnings," says the now-retired Basic, whom the Spanish TV crew filmed in his home on the nearby island of Vir. He's not trying to hide his pride when he says Modric called him the day after he signed for Real Madrid. But pressed to confirm the authenticity of the wooden shinpads story, he hesitates to answer. "Maybe I forget," he says. "Those could have been somebody else's shinpads." But do you still keep his shinpads, the crew asked him. "Of course I do."

It was Basic who arranged Modric's move to Dinamo Zagreb when the player was just 15, making a personal deal with Zdravko Mamic, now the Dinamo executive director and a power in Croatian football. But they didn't believe in him there, either. When he reached 18, he was sent out on loans – first to Zrinjski in Bosnia and Herzegovina, probably the most brutal European league at the time, then to Inter Zapresic in the suburbs of Zagreb.

Modric was brilliant in each of those two spells and came back to sign a 10-year contract with Dinamo Zagreb. That finally enabled him to repay his family for the faith they invested in him, so he bought them a nice flat in Zadar and they are no longer refugees.

The rest of the story is, more or less, well known – after fantastic displays for Dinamo Zagreb and Croatia, Modric was sold to Tottenham. Now he is trying to establish himself at the Bernabéu. After all he has been through, it should not seem too difficult.

Follow Aleksandar Holiga on Twitter at @AlexHoliga