IT IS one of West Cork’s most celebrated pubs. MacCarthy’s, located in pretty Castletownbere on the Beara Peninsula. It, has been welcoming tourists and locals alike for years and its striking facade features on the dust jacket of Pete McCarthy’s celebrated travel book, MacCarthy’s Bar.

It is here that you will find Niki and Adrienne MacCarthy - and a magnificent ceremonial sword from Japan that helped lead the sisters on a hunt to uncover their father’s astonishing wartime story.

“My father had been a prisoner of war in Japan and had brought the sword home with him,” Niki says, “but he didn’t like to talk about that period in his life. It was only in the period leading up to his death 20 years ago that he would talk about it and we started to understand just what he had been through and what the significance of the sword was.”

Dr Aidan MacCarthy’s wartime experience is the subject of a striking new documentary, A Doctor’s Sword, which sees Niki journey to Japan to get a sense of what her father had been through and to see if she could find any relations of the man who gave her father the sword.

Aidan MacCarthy was born in Castletownbere in 1913 and despite spending the majority of his adult life in the UK, he never lost his Cork accent.

He studied at the private Clongowes Wood College in Dublin, a time that charged a life-long love of rugby. In fact, he won a coveted Munster trophy with UCC’s rugby team when studying medicine there in the early 1930s.

He found it difficult to get work as a doctor in the Ireland and was forced to emigrate to, first Wales, and then England, in order to make a living.

When the Second World War broke out, he, like many Irishmen at the time, felt compelled to join the Allies in their war against Germany.

After a night out in Soho, the doctor and two of his Irish friends joined the Royal Air Force (RAF), in his capacity as a medic, and would soon witness at first hand the horrors of conflict on continental Europe.

Among those horrors was the ‘Miracle of Dunkirk’, the massive rescue operation undertaken amid constant aerial bombardment. Dr MacCarthy spent three days sheltering from the attacks before rescue, but a kilometre out to sea, the vessel was torpedoed with numerous casualties.

Somehow, the badly damaged ship it made it back to England with Aidan tending to the sick in a makeshift operating theatre.

Traumatic as that was, it would be nothing compared to his experiences in the Far East.

But first, he was to win the George Cross for bravery after saving the lives of aircrew who had crash-landed at the RAF base he was stationed at: despite the plane threatening to explode at any moment, coupled with the attacks from Luftwaffe fighters overhead, Aidan and a colleague pulled the two surviving airmen clear.

“When you consider all that he went through before he even went to the other side of the world, it’s remarkable that he didn’t want to talk about it,” Niki says.

“But a lot of people from that generation were like that. They took tough experiences in their stride and got on with things. He would certainly need all his reserves of strength - both mentally and physically - from then on.”

When the Japanese started bombing the then British colony, RAF Spitfires and Hurricanes were sent and Aidan arrived shortly before the city-state fell to the Japanese.

He was among thousands of soldiers who were rounded up and sent to a PoW camp in the nearby island of Java.

A Doctor’s Sword makes it clear that he suffered a torrid time, with beatings and psychological torture routinely dished out. Summary executions took place frequently and even those who tended to be left alone had to subsist on severe food rations.

Aidan’s training as a doctor would be put to good use, albeit in an improvisational capacity considering the spartan surrounds of the camp.

He devised diets to help combat dysentery and malaria and he smuggled yeast cultures hidden in rice balls to use as a protein drink to help the sick.

With Japan’s war effort necessitating slave labour in its factories, PoWs were shipped to mainland Japan from Java and elsewhere, and in April 1944, Aidan MacCarthy found himself on a ship with 980 other prisoners.

For the second time in his life, he sustained a torpedo attack - and survived.

The direct hit from a US battleship meant all but 40-odd PoWs were killed. Aidan’s luck appeared to be intact when he was picked up by a Japanese destroyer after 24-hours clinging to the ship’s debris.

But when the crew discovered it was PoWs they had picked up, and not Japanese crewmen, they started beating them and throwing them overboard. Aidan had no choice but to jump off the deck and take his chances in the sea. He was rescued by a whaling craft and brought to Nagasaki where he was immediately interned in a PoW camp.

Once more, he suffered horrendous beatings that would later require extensive surgery but his psychological fortitude was immense.

“I don’t think it would be possible to survive without having such mental toughness,” Niki says.

The documentary shows her visiting the site of the camp at Nagasaki, and she found herself moved to be in the place where her father had been forced to spend his early 30s.

Later, he said, he kept himself sane by thinking about the little details of Castletownbere and the people who lived there.

If Dr Aidan MacCarthy’s experience reads like one horrific occurrence after the next, the worst was yet to come.

In a move that would bring the Second World War to a close, the Americans dropped an atomic bomb on Nagasaki.

Aidan was in an air-raid shelter at the time and survived one of two of the most devastating attacks mankind has ever known (the other, the atomic bomb dropped on Hiroshima three days earlier, was not then known by the PoWs).

In a 1995 interview with RTÉ, which forms the backbone of the film’s narrative, Aidan spoke about how their world changed in a second, how on exiting the shelter, they found that not only had the camp been levelled and scored, but the entire city had been too. When black rain - a disturbing by product of the bomb - began to fall, the doctor and the other disoriented survivors thought it was the end of the world.

Once more, his skills as a doctor would be put to use as he tried to help those people they came upon who hadn’t been scorched to death.

But once more their luck ran out when they were captured and sent to yet another hard-labour camp away from Nagasaki.

Their stay there would be a mercifully short one after the Emperor of Japan surrendered.

With many of his colleagues in vengeful mood, Aidan had the peace of mind to lock the commander of the camp in a room for his own safety. After the camp was liberated, the commander handed the Irishman his ceremonial sword, which in Japanese military custom is considered one of the ultimate examples of gratitude.

Remarkably, Niki and director Gary Lennon manage to make contact with the commander’s grandson and there is a touching moment in the film when they meat at the graveyard where he was buried.

“I couldn’t believe our luck that this man had seen the article about us that had appeared in the Japanese newspapers and, despite the traditional reserve of the people was willing to get in touch,” Niki says.

“Going to Japan helped me realise that while my father suffered greatly, so did the Japanese people too. The atomic bombs had a devastating impact.”

Niki, who was born in Cork city, lived a nomadic life with her father and mother (who was from Galway and died two years ago aged 97), but she moved to Castletownbere 25 years ago and now helps Adrienne, who runs MacCarthy’s.

Aidan, on retiring from the RAF, continued to work as a doctor for many years. “Going on this journey has given me an appreciation of what a remarkable, resilient man he was, and also made me think of the bravery of so many Irish men who fought for the British in the war but who have been forgotten.”

For filmmaker Gary Lennon, A Doctor’s Sword is the fruit of a five-year process and he hopes it will shed light on an unsung hero.

“Even though I never met Aidan MacCarthy,” he says, “I feel I know him very well. Not only is his story quite incredible, but he managed to live a comparatively normal life afterwards despite the physical and mental suffering he experienced. That’s really something.”

A Doctor’s Sword goes on limited release from August 7, with screenings at Dublin’s IFI and Cork’s Mahon Point Omniplex.