My father likes hunting and I want to please him. But nothing prepares me for the beauty of the stag I was expected to photograph

I don't like bloody sports. But, growing up in the luxurious countryside of Northumberland in the 1980s, I expected it to be like this. When my father who grew up in Tyneside moved to the country in the 1970s, he soon began accepting invitations for pheasant shooting, grouse marshes, and fishing expeditions. He likes company, sports and time spent in the wild.

From about eight years old, I was invited to accompany him on these weekend excursions, just like a child was brought to their first football match. I don't like getting up early, standing in a cold environment, waiting for the birds to fly into the sky, kill them, and pass through the row of rumbling gunfire. But I want to please my dad. However, when I grew up to make my own weekend plans, I made them. They tend to focus more on buying clothes and going to the Metrocentre in Gateshead to watch movies.

So why many years later — I was 27 years old and working for a film company in London — I accepted the invitation to go to Scotland with my father to track deer, I don’t know. except me. It is offered as a family holiday in the beautiful West Highlands. We visited the area often when we were young, and I was nostalgic for the magnificent scenery and spectacular hills. I still want to please my father. I even took a 0.22 rifle course at his request-when I tried to shoot a paper target with it for the first time, it flinched in a poetic twist of justice and made my eyes black.

The hunting team gathered on a Friday in September at the turn of the century. At dawn the next day, we started riding in Argocat, an open-top eight-wheeled military vehicle that can climb a nearly vertical slope at extremely fast speeds. The driver is also our ghillie, a strong and sturdy person. His job is to identify the old or frail deer that is selected for elimination and guide us through wind, fog and rain.

Geely is stronger than the hills themselves. He hurriedly made us walk around the bare mountain peaks so frequently that I almost thought we were training for falls. As time goes by, it feels more and more like Bucannes-style special operations missions. We were instructed to slide on the rocky river bed on our stomachs, rifles clinking on our backs. We waded through the swamp and climbed over the swamp peaks. As our quarry moves, we keep changing directions.

"Why are you doing this?" I kept asking myself. "What's the problem with walking? Or a guided wildlife tour?"

Then, all of a sudden, Geely almost pushed me to the ground. He pointed to a cloud of mist about a hundred yards ahead. I was confused until the clouds rose up like a curtain and appeared in front of us-this is one of the most spectacular creatures I have ever seen.

I can still see the stag so clearly in my mind. Those staring black eyes and big black noses almost like dogs, rows of skeleton antlers and fluffy fur, with grey marble patterns. He is old, but still majestic-and healthy enough to lead us to dance happily on the hills. "Now!" Geely hissed in my ear. "Now your chance is here. Remember. You want to kill it, not hurt it."

I adjusted my position, focused the scope again and put my finger on the trigger.

And, of course, I cannot shoot. What am I thinking? I don't think I'm looking at an old beast that needs to be culled. Ghost, against the backdrop of the mountain peaks at the top of the cloud in the distance, he looks more like the faded ruler of an ancient kingdom. I looked into those eyes, put down my rifle, and listened to the groans of Geely and my companion. Another mist fell; when it rose, the stag disappeared a few seconds later.

I picked up my rifle and brushed off the grass and mud. The rest of our party continued, and I struggled back to our holiday house. But I am not depressed. I am very happy. I came—through a telescope—to face one of Britain's most beautiful, iconic and noble beasts, roaming freely in his own desolate and desolate land.

This is a real moment and lasting inspiration. I can never kill that stag-under any circumstances, for any reason. But ten years later, I will write a story about him. Not just one book, but four books about a young boy and the stag who convinced him to help save the world's only remaining animal. The encounter with that majestic stag changed my life. Guess what-these stories really make my dad happy.

Piers Torday's latest book The Wild Before (Quercus Children's, £12.99) is now out. To support The Guardian and The Observer, please order your copy on Guardianbookshop.com. Shipping costs may be charged.