He doesn’t know anything about her, except that she was the first reason he didn’t turn and flee after he watched the second plane slice through the South Tower a block away, the reason why, as dozens of dust-covered men and women rushed past him, he ran toward the Twin Towers. He scooped up the woman and set her back on her feet a couple blocks away.

And then he headed back to the burning buildings. His cousin, Lizie Martinez-Calderon, who he’d been singing with in church choirs and at family events for nearly 20 years and who had told him just two days earlier, “You are so in!” after she’d submitted his resume for a public relations job at Aon Insurance so they could work there together–was still inside.

He never found her.

Guerrero doesn’t like to dwell on the dead, but that doesn’t mean he doesn’t think of them. One year after the attacks, thoughts of his cousin and the hundreds of others who perished that day are still fresh in his mind. He still cannot shake the memory of the hand he saw extended from the rubble after the buildings collapsed, as if reaching for help. “I went to pull it, and there was nothing more–it was just a hand,” he says, taking off his glasses and wiping his eyes. “I don’t talk about that much.”

He doesn’t talk a lot about how much he misses his cousin either. But on the chain that hangs from Guerrero’s neck, behind three Salvation Army ID cards (one he saved from last September that gave him access to the recovery site), he carries a laminated photo of his cousin taken on the day of her high-school graduation. He wears it every day; it falls just above his heart. “People say, ‘oh, you were just cousins,’ but we were so close,” he says.

The two of them shared a strong spiritual faith, a talent and penchant for singing and an affinity for white roses, which they exchanged on birthdays and special occasions. Today, Guerrero–who is 33, the same age his cousin would have been this year–carried a vase with two freshly cut white roses to the site where she died. As his cousin’s name and those of 2,800 others who died a year ago were read aloud, he placed the roses in a “Circle of Honor” memorial on behalf of her two children, ages 2 and 4, and her husband, Marino. A close friend, he had called Guerrero early Monday morning, unable to sleep, and told him he could not bear to attend the ceremony, could not even bear to be in New York on the anniversary, and that he was going to take the children out of town. Guerrero arrived at the World Trade Center site at 5:45 a.m. to get his ID and pass out water and granola bars to the police officers around the site–then he joined the line of family members himself.

“There are people who say that I was so lucky not to have been there, not to have gotten that job [at Aon],” says Guerrero. “But I think there’s no such thing as being lucky. When someone so close to you died that day, it doesn’t make you feel any better to know you could have been in there and weren’t.” Maybe that was why it was so difficult for him to leave Ground Zero during–and even in the weeks following–the attacks.

On September 11, 2001, Guerrero had been working as an assistant chiropractor. On Tuesdays, he would set up a table in the plaza in front of the World Trade Center to distribute information on the nearby practice. But he never had a chance that morning to set up the table.

Guerrero, along with others who felt compelled to stay after the attacks, was finally ordered by police to leave the disaster site and gather instead at the fountain in City Hall Park a few blocks away, where they were sorted by skills. Someone wrote “CPR” in marking pen on Guerrero’s shoulder (he had earned a certificate after taking a first-aid course), and sent him to the “med” group. Shortly after that, the group was picked up by a city bus that zigzagged its way back to what was now a smoking pile of rubble; both towers had collapsed. They were dropped off near the West Side Highway where a triage tent was being set up and mobile canteens were arriving with food, water, clothes and medical supplies. Guerrero handed out water, then he found a Salvation Army tent and helped clean out the eyes of rescue workers and police officers with donated saline solution. He moved around the site, volunteering wherever he was needed. He didn’t sleep for three days and two nights.

On the third night, Guerrero remembers that it rained steadily and he finally walked home–20 blocks–to the apartment he now shares with his sister. He doesn’t remember much more about that day. “I think I was still in shock,” he says now. The Dockers jeans, penny loafers, and expensive, freshly pressed white shirt he had been wearing when he set off for work on September 11 were by now so filthy that he had to throw them out. After a few hours of sleep and a shower, he set off for the site again in a new uniform: a flight suit his cousin, Luis, a U.S. Marine, had sent him the week before. It was a special suit, and not just for sentimental reasons. The material was fire-resistant.

When Guerrero returned to the smoldering pile, one of the Salvation Army officers recognized him and arranged for him to get a badge and a volunteer job in the canteen unloading and delivering supplies to rescue workers. Later that day, he heard a public-service announcement for charitable donations that began with sound bites of the sirens and the screams of workers scrambling to escape from the buildings and ended with a young girl’s voice: “Why did so many people have to die?” And, for the first time, Guerrero cried.

He remained with the Salvation Army officers as a volunteer for more than three weeks. He often forgot to sleep or to eat; he lost 30 pounds. When he’d call his mom from the pay phone to check in, she would plead with him “Why don’t you come home? Why don’t you leave?”

But he says he couldn’t. And where would he go anyway? The chiropractors’ office where he’d worked had been damaged in the attacks and was closed. Besides, he says, he felt like he belonged down there. There was a lot of work to do. Finally, in October, he tried to go back to work in the chiropractors’ midtown office location. But each day reminded him of the attacks. Nearly all of his clients had worked in the World Trade Center–and many of them had died there. “It was just too hard,” he says.

He quit after a week and was in the midst of looking for another job when he woke up on Nov. 12 to the news that an American Airlines jet had just crashed in a residential neighborhood in Queens. When he heard about the plane crash, he instinctively got dressed and ran three blocks to the Salvation Army headquarters. The aid organization had already sent a van of workers and volunteers to the site of the plane crash, but Guerrero offered to stick around in case they needed more help. “How much time do you have?” asked the woman at the main desk.

Nine months later, Guerrero is still getting dressed every weekday morning and walking over to the Salvation Army headquarters, where he now has a paid position. He began as a volunteer coordinator for a Thanksgiving dinner, then organized a toy giveaway for hundreds of children affected by the World Trade Center disaster and was finally hired on as a full-time assistant case worker for those who lost wages or loved ones because of the terrorist attacks. “You lost somebody? I understand. You lost a job? I understand,” he says. “I think I ended up in the right place, just knowing that I’m helping someone every day.”

That’s how his cousin was, he says–even at the end. Not long ago, her former boss at Aon came up to him at a memorial service. He told Guerrero that Martinez-Calderon had urged him to leave the building that morning, had assured him that she would stay and take care of things in the office. “It’s because of her that I am alive,” he told Guerrero.

In the bedroom of Guerrero’s apartment, he keeps a newspaper clipping of his cousin with a photo of her wedding day and one of her holding her daughter. Beside it hangs the flight suit he wore when he volunteered at Ground Zero in the days after the attacks. He has sewn up a tear in the arm and carefully Velcroed the patches from his other cousin’s Marine unit back into place. Around it, he has placed his Salvation Army helmet, along with a harness, military belt, and two respirators he was given during the recovery effort, and a pair of boots someone had donated with the words GOD BLESS AMERICA written on them. “I keep them there just in case,” he says. “In the back of my mind, I know if anything happens again, I’ll be ready to help.” Just as he was on September 11.