An impoverished teenager, Mehdi, joined the wave of Afghans who left their homeland, dreaming of reaching Europe to find work.
Where he ended up was entirely different: On the battlefields of Syria's civil war, in a militia created by Iran.
Mehdi was one of tens of thousands of Afghans recruited and trained by Iran to fight in support of Tehran's ally, Syrian President Bashar Assad.
In Syria, he was thrown into one of the war's bloodiest battles, surrounded by the bodies of his comrades, under fire from Islamic militants so close he could hear their shouts of "Allahu akbar" before each mortar blast.
Iran created a network of militias made up of Shiites from across the region and used it to save Assad from the uprising against his rule not only Afghans but also Pakistanis, Iraqis and Lebanese.
Now with the 8-year war in Syria winding down, the question is what will Tehran do with those well-trained, well-armed forces.
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Mehdi and other soldiers-for-hire from Afghanistan's impoverished Shiite Muslim communities are returning home, where they are met with suspicion.
Afghan security officials believe Iran is still organising them, this time as a secret army to spread Tehran's influence amid Afghanistan's unending conflicts.
"Here in Afghanistan we are afraid. They say we are all terrorists," said Mehdi, now 21 and back in his home city of Herat.
He was terrified, speaking on condition he not be fully identified for fear of retaliation.
He met The Associated Press in a car parked in a remote, mostly Shiite neighbourhood, and even there kept his face obscured with a scarf, glancing suspiciously at every passing car.
The returning veterans are threatened from multiple sides.
They face arrest by security agencies that see them as traitors.
They face violence from the brutal Islamic State affiliate in Afghanistan, which views Shiites as heretics and vows to kill them.
Last May, IS gunmen attacked a Shiite mosque in Herat, killing 38 people.
To back Assad, Iran sent hundreds of Revolutionary Guard troops to Syria and brought in a number of allied militias. The most well-known and most powerful was Lebanon's Hezbollah.
But the largest was a force made up of Afghans, known as the Fatimiyoun Brigade, which experts have estimated numbered up to 15,000 fighters at any one time.
Over the years, several tens of thousands of Afghans trained and fought in it, most from the ethnic Hazara minority, who are among Afghanistan's poorest.
Roughly 10,000 veterans of the brigade have returned to Afghanistan, says a senior official in Afghanistan's Interior Ministry, who spoke on condition of anonymity.
The Afghan government and many experts believe Iran could mobilise these ex-fighters once more, especially if the country's many armed factions turn on each other in escalated warfare after US and NATO troops withdraw.
Iran could use the chaos to deploy the brigade, with the very real pretext that the vulnerable Shiite minority needs a defender.
"Expect the Iranians to reconstitute their militias inside Afghanistan at some point," said Bill Roggio, editor of the Long War Journal, a site devoted to coverage of the US war on terror.
"Iran does not discard assets in which it invests time, treasure, and expertise."
"I decided, 'Live or die, I'll go'."