Pvt. Johnnie Stevenson cleaned his truck one last time, scraping off the barnacle-like mud and pulling crushed water bottles from under seats. But deployment to Afghanistan was almost over, and his thoughts drifted elsewhere. Was his pregnant fiancee ready to be a mother? Facebook provided so few clues. Nor could it answer him this: Was he ready to be a father?

Capt. Adrian Bonenberger made plans for his final patrol to Imam Sahib. But inside, he was sweating the details of a different mission: going home. Which soldiers would drive drunk, get into fights or struggle with emotional demons, he wondered. What would it take to keep them safe in America?

Sgt. Brian Keith boarded the plane home feeling a strange dread. His wife wanted a divorce and had moved away, taking their son and most of their bank account with her. At the end of his flight lay an empty apartment and the blank slate of a new life.

“A lot of people were excited about coming home,” Keith said. “Me, I just sat there and I wondered: What am I coming back to?”

For a year, they had navigated minefields and ducked bullets, endured tedium inside barbed-wired outposts and stitched together the frayed seams of long-distance relationships. One would think that going home would be the easiest thing troops could do.

But it is not so simple. The final weeks in a war zone are often the most dangerous, as weary troops get sloppy or unfocused. Once they arrive home, alcohol abuse, traffic accidents and other measures of mayhem typically rise as they blow off steam.

Weeks later, as the joy of return subsides, deep-seated emotional or psychological problems can begin to show.

In their new normal, troops must reconnect with children, adjust to more independent spouses and dial back the hypervigilance that served them well in combat — but that can alienate them from civilians.

“The hardest part for me is, I guess, not being on edge,” said Staff Sgt. Francisco Narewski, a father of three who just completed his second deployment. “I feel like I need to do something, like I need to go on mission or I need to check my soldiers. And I’m not.”

For the 1st Battalion, 87th Infantry out of Fort Drum, N.Y., which recently finished a yearlong tour, leaving Afghanistan proved as deadly as fighting in Afghanistan. In the first 11 months of deployment, the battalion lost two soldiers, both to roadside bombs. During the next month, it lost two more, neither in combat.

On March 9, the day before he was scheduled to leave Kunduz, Spc. Andrew P. Wade, 22, was accidentally shot and killed by a friend who was practicing a drill with his 9-millimeter pistol inside their tent.

Three weeks later, Spc. Jeremiah Pulaski, who had returned from Afghanistan in February, was shot and killed by a police officer after he shot and wounded a man outside a bar in Arizona. He was 24.

FINAL WEEKS

In Kunduz and Baghlan provinces, war defied the usual rhythms last winter. American forces typically hunker down in the cold months to await the spring fighting season. But from October to January, American, German and Afghan forces cleared several major insurgent strongholds.

By February, the Afghan police were conducting regular patrols alone into places they had refused to visit without American forces just weeks before: Gor Teppa, Chardara and Aliabad in Kunduz, and Dahana-i-Ghori and the Golden Triangle north of Pul-i-Khumri in Baghlan.

Even a slice of Dasht-i-Archi, where the stoning of an adulterous couple last year became a worldwide symbol of the Taliban’s resurgence, was cleared of mines and insurgent checkpoints.

Through the winter campaign, only a handful of American soldiers were wounded, and none died.

Still, there was much debate among American soldiers over whether the stability would last.

Then came a series of attacks that made it clear the insurgents were not gone. In early February, the governor of Chardara district was killed by a suicide bomber. Two weeks later, a bomber detonated a powerful device in Imam Sahib, killing 30 people, most of them civilians. And in early March, another suicide bomber assassinated the police chief of Kunduz province.

JOURNEY HOME

The string of winter operations against the Taliban had given many soldiers a sense of accomplishment that was missing in the fall, when morale, like the temperature, was sinking. By the end of the tour, spirits were high and pranksters were afoot, hogtying officers in their beds and stealing clothing from showering soldiers.

Just getting the battalion’s nearly 800 soldiers home was far from simple. It would take a month, along with dozens of helicopters, military cargo planes and commercial jets, to move them the 6,500 miles to Watertown, N.Y.

On his final flight home, Stevenson, 20, fantasized about the freedoms he would soon taste again: texting anyone anytime, wearing blue jeans and T-shirts, taking his little brother to the zoo. Being alone.

His deployment had been a mixed bag. After getting into an argument with a higher-ranking soldier, whom he half-heartedly threatened to kill, he lost a rank. But he had also performed well under pressure.

While driving his platoon leader on a mission last fall, his truck hit a powerful mine that blew off its rear end and flipped it over. Stevenson was the first out and helped the three other passengers, including his lieutenant, escape. He earned a Purple Heart after sustaining a back injury and a possible concussion in the explosion.

As the plane approached New York, he was thinking about his next big challenge. His fiancee was pregnant, and he was so excited by the prospect that he planned to buy baby furniture and diapers as soon as he got home. More than ever, he thought he should get out of the Army and try college.

“I want to be there for my kid’s first steps; I want to be there for his first bicycle accident,” he said. “I kind of think the Army is not for me, family-wise.”

REUNIONS

A wet snow was falling as Narewski’s charter DC-10 touched down at Wheeler-Sack Army Airfield in March. He bounded off the plane beaming like a boy heading into summer vacation.

“I love America,” he shouted as he sprinted to the terminal.

His unit went through customs, turned in weapons and received safety briefings on base speed limits, malaria pills and mental health counseling. Then they waited. Finally, at 6 a.m., they boarded yellow school buses and headed to the Fort Drum gymnasium.

In the bleachers sat his wife, Christina, with their three children.

As the soldiers marched into the gym, she craned anxiously in search of her husband, squirming with impatience as they croaked their division’s song out of key. She kicked off her high heels, and as soon as a commander shouted “Dismissed!” she sprinted across the hardwood floor.

“Everybody was laughing at me, but I ran,” she said. “That’s all I remember, is running.”

For minutes, time enough for some couples to hug and leave, she buried herself in Narewski’s broad arms, whimpering. “Just to have him hold you or be in his arms again is just the greatest,” she said. “You think about that not happening while he’s gone.”

This second deployment of his had been harder than she anticipated. To her delight, Narewski, 31, accepted a drill sergeant assignment at Fort Jackson, S.C., a two- to three-year tour with no deployments.

Being a drill sergeant would be good for his career, the sergeant said. But inside, he was still thinking about leading soldiers into combat. “I love it,” he said. “I’m going to miss it. I miss it already.”

In the weeks after the battalion got home, Bonenberger, 33, moved into an apartment with two fellow captains and considered his future. Should he accept a teaching position at West Point or get out of the Army?

Stevenson married and learned that his child, due in August, was a boy. He bought an SAT prep book.

And Spc. Matthew Hayes, who had lost his leg to a land mine and was undergoing rehabilitation at Walter Reed Army Medical Center, visited his platoon mates at Fort Drum. To celebrate, they drank Guinness from his prosthetic leg.

© 2011 The New York Times Company