Sitting cross-legged on the cushioned floor of a family friend's house, Mohammed Jawad furrowed his brow and fidgeted nervously as he struggled to explain his extraordinary ordeal over the past seven years.
In December 2002, when he says he was only 12, he was arrested on suspicion of throwing a grenade into a Jeep carrying US special forces soldiers through Kabul, wounding two of them and an interpreter. He was taken first to an airbase north of Kabul, then to the US prison in Guantánamo Bay, where he remained until his release a few days ago after a ruling by a US judge that his confession had been obtained by force.
One of the youngest and most controversial prisoners in Guantánamo, Mr Jawad is now finally a free man after being flown back to Kabul on Monday and reunited with his family and friends.
But after seven years in custody - six of them in Guantánamo - he faces a long struggle to pick up the pieces of his lost childhood and teenage years, and to build a future for himself in a country still at war with the Taleban.
"This is one of the happiest moments in my life - to be back in Afghanistan after all this time," he told The Times.
"I hadn't done anything - they took me for nothing. All I could do was hope that one day I'd be free and back home in Afghanistan with my mother."
When he was reunited with her, she refused initially to believe he was her son because he had changed so much, and fainted in a fit of hysterics, according to a family friend. Only when she came round and checked for a distinctive bump on the back of his head, did she embrace him as her offspring, said Sher Khan Jalalkhil, a close friend of Mr Jawad's father.
Mr Jawad is not the first Afghan prisoner to be released from the Guantánamo prison. But he is believed to be the youngest - although the Pentagon says that bone scans indicated that he was 18 when sent to Guantánamo in 2003.
He has thus become a cause célèbre for human rights activists ... and something of a celebrity in Afghanistan. President Karzai even offered to give him a house in Kabul when he met him on Monday night. The Defence Minister, Abdul Rakhim Wardak, offered to pay for him to study overseas.
When Mr Jawad was arrested, he was living with his mother in Kabul - his father having been killed fighting the Soviets in the 1980s.
"We searched for him for nine months," said Mr Jalalkhil. "We didn't know if he had been killed, or kidnapped, or got lost. His mother went crazy." Finally, a member of the International Committee of the Red Cross visited their house to show them documents proving that Mr Jawad was in Guantánamo.
They were relieved at first to hear he was alive, but then they started to hear reports about conditions there.
Since returning, Mr Jawad has accused his captors of torturing prisoners, depriving them of food and sleep, and insulting Islam and the Koran.
He has described having his hands bound and stretched behind his back, and being forced to eat by bending over and putting his mouth into a plate of food.
Yesterday he was reluctant to go into details, saying that he would describe everything in full at a press conference in Kabul today. "It was a jail and I wasn't happy there - I didn't feel very good," he said, shrugging his shoulders. "They threatened me a little. I will tell all of this tomorrow." Human rights activists say that he was moved around often, and in one seven-day period was subjected to 152 episodes of mistreatment.
Eric Montalzo, his lawyer, says that he was treated like an adult despite his young age. "He has been in a cage for seven years. So it's very difficult for him," Mr Montalzo said. "He is a fragile human being and we need to protect him and his interests."
Navi Pillay, the United Nations High Commissioner for Human Rights, said that there should be compensation for prisoners such as Mr Jawad, and no immunity from prosecution for the torture of terror suspects.
Some human rights activists accept the Pentagon's assertion that Mr Jawad was 16 or 17 when arrested. But they also say that it could take years for him to recover from the trauma of being detained in such a way for so many of his formative years.
Mr Jawad, meanwhile, is making plans to resume his studies - first in Afghanistan, then maybe overseas - and train to become a doctor.
Asked if he would consider studying in the United States, he hesitated and looked to the assembled elders for advice, before answering: "I have not made any plans yet." As the interview began, the elders had asked him teasingly whether he learnt English in Guantánamo. He said no and spoke only in his native Pashto during the interview.
But when thanked at the end, he smiled shyly and said, with only a slight accent: "No problem."