For my wife Cathlin’s last day of radia tion treatment for breast cancer, the kids and I head into Boston to be with her. Eirene, aka Pickle (age four), decides to dress as the hobbit Frodo Baggins. Her costume includes a pair of blue jeans, a white mesh shirt she says is the elven material mithrail, and a long turquoise cape. She also insists that her face be rubbed with mud, as during Frodo’s travels to Mordor he was often dirty.

Hardy (age seven) wears the same pants and shirt he has worn nearly every day for the past few months. Making him change his clothes is just one of many things I have stopped worrying about this year.

After buckling the kids in, I sit in the driver’s seat and turn around to ask what song we should play to mark this momentous occasion.

“Psycho Killer,” Hardy shouts.

The kids and I have been listening to an old CD compilation of punk and new wave songs I found in a box in the basement. The sound track of the Sex Pistols, Blondie, Elvis Costello and the Talking Heads have marked this cancer time with an appropriate mood, I think. We three are a raucous group and when we drive, we play it very loud.

“Gloria,” Pickle suggests after I say Psycho Killer might not be appropriate for this moment. She waves her sword in the air and with her flock of corkscrew curls she does indeed look like a hobbit.

“Perfect,” I say about the Patti Smith anthem. We pull out of our driveway, heading down-Island to pick up my mother and Cathlin’s sister and then to the ferry. It is a bit like a family road trip with music and snacks and head-banging tunes.

The end is near and I can’t believe we have all made it through, changed but still whole. We have been extremely open with the kids and I think to myself that they, especially, have weathered the journey well.

After we drive a bit, Pickle calls to me from the back seat. I turn the music down.

“What is it Pickle?”

“Did Patti Smith die of cancer?” she asks.

Cathlin has lived in Boston for most of the six weeks of her radiation treatment, the last phase in this cancer journey which began with her diagnosis last November. During her two surgeries and chemotherapy I was with her for each step, sitting with her as bags of brightly-colored chemicals slowly made their way into her body via an intravenous drip, or walking with her down the hospital corridors and holding her hand until we finally came to a line on the floor demarcating the operating room, where I could go no further.

But for radiation, Cathlin has mostly traveled alone while I have held down the logistical house of cards back on the Vineyard. Radiation is a daily 30-minute zap and gradually the zaps and exhaustion add up. Piling on a daily commute from the Island would have been too much. Thankfully, friends offered her their apartment in Boston to stay at during the treatments.

When Cathlin calls me at night from Boston the stories trickle back about the friends she has made. Cathlin has what one personality test described as a very high woo, or win-others-over trait. When she enters a room she is preceded by her smile, something infectious and so real it feels rare and precious. You are not so much drawn to it as relaxed by it.

Because she was accepted into a study of women who contracted breast cancer at an early age (43) and that the cancer was on the left side, nearer the heart, she is being treated by a proton laser rather than a photon one. The proton machine is much more exact and able to pinpoint the lasers more precisely so not as much skin is affected. This different kind of energy does not travel as deeply into the body, thus keeping the heart safer. There are only 10 such machines in use in the U.S. and usually they are reserved for brain cancer and all manner of pediatric cases.

When hearing this information from the doctor, we only thought, great — a bigger and better machine. But what it also means on a daily basis is that Cathlin’s peer group, the people she sees every day at radiation, are not mainly those with breast cancer and a good chance of survival. Her friends are kids and adults whose cases are far more complicated and with a much less favorable prognosis.

Her closest buddy is a heart surgeon with a rare form of spinal cancer. Thankfully, she does not tell me about the children she spends time with in the waiting room.

We arrive in Boston in the late afternoon. The last radiation appointment is set for 1 p.m. the next day. That night we order Chinese food and set up sleeping arrangements for the kids. We talk about the last day, and there is a celebratory atmosphere in the room. But for me the euphoria of the drive in to Boston has given way to something else. Not a quiet reflectiveness, rather something much more unsteady.

In the morning I find it difficult to breathe and take Pickle with me in search of good coffee. She is only part Frodo now, with the cape but no dirt smudges or sword stick. We are in the city, after all.

We find a perfect cafe near the Boston Common. Afterwards, while walking back through the common, we come upon an ancient graveyard. There is a fence circling it and the headstones are both crumbling and majestic. Pickle and I pause here, she is on my shoulders now, and watch as a large hawk lands on one of the larger headstones and begins to preen himself. He cocks his head and looks directly at us. The moment is arresting and yet so peaceful and beautiful I find myself relaxing for the first time since we left the Vineyard. But I am also confused. We have looked forward to this day for so long and yet now that it has come I want no part of it.

We leave the apartment early with plenty of time to make it to the hospital. We don’t want to be late for the last day and we also want to find some fun for the kids. There is a carousel and a bit of an urban water park in the middle of the common. The water park is mostly a macadam area the size of a football field filled with shin-high water and a few fountains. It is a hot July day and after a carousel ride the kids change into their bathing suits.

Hardy begins to act up, scaring his sister and being a general nuisance. I ask him to walk with me and we move about 20 yards away to have a talk. Sometime during this cancer journey I learned I could no longer even raise my voice with my children, and instead we have small talks. I wish I could say this was because the experience of my wife’s cancer made me a more empathetic soul and able to deal with difficult situations in an enlightened way. No, I had to stop yelling because I scared myself.

One day Hardy became very frustrated before school. I believe his favorite pants were too dirty to wear and he threw a tantrum, something that would have been annoying at age four, but at age seven struck me as so wrong it was clear my son would grow up to be a horrible person.

I yelled at him. I yelled a lot but this only added to the commotion and Hardy cried louder. Finally, we made it to the car but he was still crying and I was still yelling. When we approached the school I decided we could not arrive in this state and so I kept driving. I had no plan, I just drove.

After a bit Hardy stopped crying and asked me where we were going. He seemed frightened. The anger he had been expressing minutes before had been replaced by a slight tremor in his voice. I didn’t say anything and just kept driving, enjoying far too much my son’s repeated pleas to know where we were going. Even now, while writing this, a queasy feeling stirs in my stomach. This went on far too long, my silence in the front seat and my son’s fearful questions coming from the back seat. Near the Tashmoo Overlook, a few miles past his school, I turned the car around.

We drove home rather than to school, walked inside the house and sat on the couch side by side. My adrenalin was still high, from my earlier anger but more so because I had frightened myself by becoming in effect my son’s torturer, even enjoying how much I had scared him.

I apologized to Hardy and then we talked about what had happened.

“My tantrums happen,” Hardy said, “because when something bad happens I don’t only think about that thing. I think about every bad thing that has ever happened or will happen. That’s why I can’t stop the tantrum.”

I thought about my own anger at my son, how it had little to do with the moment and everything to do with all of the other bad things that were happening. I make it through each day covered in an armor of scheduling. I compile lists of phone numbers of relatives, friends and babysitters and create flow charts detailing where the kids will be each day and with whom. I feed them and dress them and put them to bed, trying for the most part to keep them happy and almost oblivious to their mother’s cancer. And then, in the early morning before they awake, I sit alone in the dark with my coffee and discover new ways to cry. I am not a man who can afford to yell at my children. I just don’t trust myself.

At Massachusetts General Hospital we take the elevator down five flights to the basement of the building. When we walk out the doors we are treated like celebrities.

“You get to ring the bell today, right?” a man asks Hardy, who nods and smiles.

The bell is a last day of radiation tradition. It hangs from the wall not too far from the elevators. Above the bell is a large congratulations sign. Below it are the words: When My Treatments Are Done, This Bell Must Be Rung.

A nurse leads us out of the waiting room down several twisty corridors. “Radiation doesn’t like corners,” he tells us. We are all following him, the kids, mom, Cathlin’s sister Cecilia and Cathlin, too, dressed now in her gown, booties and head wrap. Before radiation began, she received five small blue tattoos, permanent dots on her body to help align where the radiation would be pinpointed. I can see two of these blue dots now, one just above her sternum, the other by her shoulder.

When we finally reach the cyclotron, I am amazed by its size. It takes up most of the room, a hulking thing that can accommodate three people at a time, each one listening to their favorite piped-in music. The machine weighs 100 tons, the nurse tell us, and is three stories high.

After a few minutes of exploring and making sure the kids don’t fall off the edge of the floor, we all hug Cathlin and the nurses and technicians, too. Then we head back to the waiting room.

My mother and Cecilia take Pickle with them back upstairs to buy flowers. Hardy meets another boy whose mom is also being treated for breast cancer and they find a computer in the kids’ room and play video games. I take a seat in the waiting room.

Next to me is a mother and father and their little girl, about 10 years old. She has crutches and wears a thick wool hat to hide her baldness.

The elevator dings and a new family enters. A boy leads the group. He wears a Little League uniform with his cap pulled down low but it doesn’t cover as much as the girl’s wool hat.

Another family arrives and I immediately look to the children; there are three of them, but everyone has a full head of hair and I wonder why they are here. Then I see they are carrying a large chocolate cake. One of the nurses runs out from behind her desk and approaches the oldest boy, who is perhaps 14.

“Oh, you look so good,” she says. “And grown up.”

“Yes, he got his hair back,” the mother says. “It makes him look older.”

The boy smiles with no trace of the shyness or awkwardness around adults that kids his age usually display. He carries the cake to the reception desk and passes plates around to all the workers.

I am not sure if this is a check-up with his oncologist or an anniversary party, maybe commemorating one year after his last treatment. In any case, this boy looks so healthy, as if nothing had ever happened to him. I feel so happy for him and yet so worried, too.

Everybody returns to the waiting room and when Cathlin joins us, there is a cheer. The family gathers around her, the staff, too, and we make our way to the bell. I find myself drifting to the edge of the crowd.

I lived in New York city during 9/11. I still remember the day very clearly, the chaos, fear and sadness floating through the streets. People were on high alert and talking to each other, even the normal barrier of strangers on the subway suddenly lifted. But not for me.

I learned on that day, among other things, that when emotions run so high, as if the internal thermometer knows no brakes, I shut down and go into survival mode. I can do tasks with a heightened clarity but all feeling goes fuzzy, almost as if my heart has been placed in a safe house in order for my mind to function.

This is how I felt in Boston. The others stepped up to that bell and rang it. First Hardy, then Pickle and then Cathlin. The nurses clapped and cheered. Cathlin’s sister cried and my mother embraced her daughter in law. I hovered in the background, wanting so desperately to be alone, perhaps reading a book in my childhood bed, covered in my football sheets and looking at the posters on the wall of my hero at the time, the Indian Crazy Horse.

After we returned home I continued to drift in this semi-darkness. The initial feeling of being unplugged worsened as I also felt guilty for not being able to celebrate. It was over, no more surgeries, chemotherapy or radiation. And I fully believed this. And yet I could barely smile. It is as difficult to describe this now as it was difficult to comprehend then.

One night Cathlin told me how she had read in one of her books about post-traumatic stress disorder being common, especially for the caregiver. This made a lot of sense, but even knowing this did not provide me with the ladder I needed to climb out of the hole.

This lasted for a long time, but gradually I began to return to my old self. There was no single moment, rather an accretion of details registering that a degree of normalcy had returned.

Getting ready to take the kids to school one morning Hardy pulled a hat out of the closet, one of Cathlin’s that she had worn to hide her baldness. He picked it up and looked at it for a moment.

“Oh, this is from when Mommy was having breast cancer,” he said. He spoke out loud as if confirming to himself the news that the cancer was indeed in the past tense.

Another day I came home from work, put my backpack down and sat on the couch as usual. I was staring at nothing when I noticed that while I was unaware, Pickle had crawled into my lap. She had become so adept at this, appearing as if by magic and snuggling in so tightly that Hardy had begun calling her a lap ninja.

I looked down at her.

“Dada,” she said. “Would you like to help me find the lost unicorn and run away from cheetahs?”

I smiled. “I would like nothing better,” I said.

The two of us tiptoed to the door and peered elaborately into the backyard looking for cheetahs. While looking outside, a flash of memory hit me. Cathlin and I were at MGH on the way to her surgery. She had already finished chemo and was thin and bald. I pushed her in a wheelchair through the hallways and noticed how others, patients and visitors, glanced at us, looked away and then looked back again. It was as if they were thinking, oh, there goes someone worse off than me or my loved ones.

And yes, Cathlin did look bad, the quintessential cancer victim. But it was during this moment that I felt a sense of peace come over me. Life’s cruelest blow had visited our house. In a way the whole family had cancer as we took care of Cathlin. After surgery Pickle chose a snuggle spot down by her mother’s feet where she would disappear under the blankets. She would lie there for hours, quietly brushing her mother’s ankles and feet. For no apparent reason Pickle called this place her jewelry box. Hardy continuously drew pictures of ray guns shooting out the cancer cells and wore a bright blue wig in solidarity with his mother.

Cecilia moved into our house to take care of the kids whenever we went to Boston for our chemotherapy weekends. Cathlin’s brother Alex and his wife Martha came to the Vineyard and stayed for six weeks to help out after surgery. My mother and father, who are retired and live here, gave up their winter months in Florida and a trip to Italy to help out in every way imaginable.

All this help from family and the community, too, was essential but in the end, it came down to the two of us who had somehow managed to find each other, fall in love, start a family and stick by each other’s side. Pushing Cathlin in her wheelchair through the hospital that day I felt an odd sense of accomplishment, as if my life really mattered.

“Hey dada,” Pickle said, interrupting my thoughts. “Is the coast clear?”

“I don’t know,” I said. “But that lost unicorn needs our help.”

We ran out of the house then and I reached down and put Pickle on my shoulders, never slowing down. As I picked up speed I felt lighter with each stride. The unicorn was out there, and we would know it when we saw it, Pickle assured me. It was the one wearing a bushy pink wig to hide its bald spot.