TAL RIFAAT, Syria — Abdul Hakim Yasin, the commander of a Syrian anti-government fighting group, lurched his pickup truck to a stop inside the captured residential compound he uses as his guerrilla base.

His fighters had been waiting for orders for a predawn attack on an army checkpoint at the entrance to Aleppo, Syria’s largest city. The men had been issued ammunition and had said their prayers. Their truck bomb was almost prepared.

Now the commander had a surprise. Minutes earlier, his father, who had been arrested by the army at the same checkpoint in July, had called to say his jailers had released him. He needed a ride out of Aleppo, fast.

“God is great!” the men shouted. They climbed onto trucks, loaded weapons and accelerated away, barreling through darkness on nearly deserted roads toward a city under siege, to reclaim one of their own.

During five days last week, Yasin and his group, the Lions of Tawhid, allowed two journalists from The New York Times to live and travel beside them as they fought their part in the war to unseat President Bashar Assad.

This group falls under the command of Al Tawhid Brigade, a relatively new structure in Aleppo Province that has unified several groups and fights under the banner of the Free Syrian Army, the loose coalition of armed rebels.

Rebellious mix

Yasin, 37, was a clean-shaven accountant before the war. He lived a quiet life with his wife and two young sons. Now thickly bearded and projecting a stoic calm under fire, he has been hardened by his war in ways he could not have foreseen.

He roams the Aleppo region with dozens of armed men in camouflage, plotting attacks with other commanders, evading airstrikes, meeting with smugglers and bombmakers to gather more weapons, and rotating through front-line duties in a gritty street-by-street urban campaign.

His fighters are a cross section of a nation at war with itself. These men fight side by side with a cadre of army defectors, who say the government they once served must fall.

The civilians started with stones and firearms bought for hunting. Their first more powerful weapon was a huge slingshot for hurling Molotov cocktails and small homemade bombs. As professional soldiers have joined them, they have gradually acquired assault rifles, machine guns and rocket-propelled and hand grenades. They now control a captured armored vehicle and two tanks, and they yearn to fight, seeking to destroy the Assad government and its better-equipped forces by most any means. Their collective confidence that they will prevail both bonds them together and informs their sense that this is their time.

Earlier that week, Abdul Hakim Yasin had left the rebels’ base for a meeting about an upcoming checkpoint attack. Jamal Abu Houran, a soldier who defected and would eventually become one of Yasin’s most trusted sergeants, issued weapons and ammunition. The fighters prayed.

Yasin returned in a rush, honking his truck’s horn. He shouted that his father had called and said he had been unexpectedly let out from prison. They needed to rush to retrieve him. The men cheered, climbed onto their trucks and sped south toward Aleppo.

In the lead truck, Yasin repeatedly tried to call a friend he had sent ahead in civilian clothes in an empty freight truck. He was expecting a trick, and wanted the lead driver to ensure that his father actually was free and there was no trap. Then the fighters could drive in.

At the outskirts of the city, he reached the other man, who reported that he was with Jamal Yasin, driving north.

For a moment, Yasin seemed less the guerrilla commander than a son. He ended the call. He drove in silence, letting the news sink in.

In the darkness of the abandoned road, the other truck approached and stopped. Jamal Yasin climbed out. He was a straight-backed and squarely built man with a shaved head. He looked unhurt.

Abdul Hakim Yasin admitted to his worry.

“I was 99 percent sure it was an ambush,” he said.

His father listened, then gently admonished his son.

“You really think if it was an ambush I would call you?” he said. “Even if they were slitting my throat?”

“Daddy, I swear to God I am under big pressure,” Abdul Hakim said.

“Take it easy, my son, there is no stress,” the father answered.

Abdul Hakim Yasin dropped off his father at his brother’s home in Tal Rifaat. The fighters stood outside, exhilarated at the reunion, shouting thanks to God. Yasin drew his pistol and emptied it into the night sky. He was grinning.

“Let’s go,” he said.

Setback and conflict

There was an attack planned, a long-discussed assault on a military checkpoint that would allow the rebels easy access to Tal Rifaat.

The attack would begin shortly, Yasin said, timed to begin about an hour before dawn.

Abu Hilal, a prisoner from the Syrian military who was told he was being used as a possible ransom, huddled against the wall, watching.

Just before leaving, he was led outside blindfolded and put into the back seat of one of the pickup trucks.

He quickly walked through a large hole cut in the compound’s back wall and approached a flatbed truck. The bed held a stack of thick pipes packed with homemade explosives. Electrical wires protruded from their back ends, all of them joined in a trunk line. This was a truck bomb, wired to detonate remotely.

Yasin revealed more of his plan. The assurances that Hilal would be released had been a deception. The fighters intended to put him behind the wheel of the truck bomb near the checkpoint and tell him to drive forward in a prisoner exchange, detonate the bomb and signal an assault.

But shortly after sunrise, the fighters returned. They trickled back in, clean and unbloodied.

They had arrived near the checkpoint, he said. All appeared perfect for the attack.

“We told Abu Hilal, ‘Go, drive that way, your father is waiting for you there, don’t do any bad things in the future,’” Hakim said. “And he was so happy, and he drove.”

Abu Hilal stopped the truck at the checkpoint. Abdul Hakim Yasin pushed the button on the remote detonator, ready for the flash and thunderclap of more than 650 pounds of explosives.

Nothing happened.

He pushed the button again.

The truck did not explode.

Yasin suspected that the checkpoint was equipped with a jammer that blocked the signal.

Now he sat in his office, disappointed at the failure, amazed that his own family remained intact. He was exhausted. Everyone he had expected to die — his father, his prisoner, the soldiers at the checkpoint — was alive.

“It is,” he said, “the game of fate.”

A few hours later, back in camouflage, Abdul Hakim Yasin led his fighters to Aleppo. Their assignment at the checkpoint had ended; they were due back at the front lines.

The commander steered wide of the checkpoint. He chose another, longer route, driving with the trucks spread out and at headlong speeds, to limit exposure to attack helicopters and jets.

Once within the city, the trucks weaved through neighborhoods until reaching a cluster of buildings under rebel control.

As they approached, gunfire ripped by. The convoy turned into an industrial compound, and the fighters hopped off the trucks, parking them against the warehouses, and fanned out.

A jet showed up and circled overhead. It was invisible in the almost moonless night sky; only its engine could be heard. Soon it attacked, too, diving toward the compound and firing air-to-ground rockets in pairs.

It pulled out, circled, returned, dived and released rockets again. They slammed to earth at the compound’s edge.

In the climate of many conflicts, this might be read as a dispiriting, lopsided encounter. The rebels could not see the aircraft. Even if they could, they had nothing with which to fire back effectively.

But as the rockets struck, the Tawhid fighters were barely distracted. They were waiting for the government soldiers nearby to show themselves, certain that night by night their foes were growing weaker, and their uprising was gaining strength.