Looking down at him now, I'd do anything to make us right. I hear the echoes of his cries from the day before, when he was lying on a hillside with medical personnel scattered about, tending to him.

Five minutes into his maiden ride on a genuine trail, six months after taking his first ride ever, traveling among two adult guides and me, still just five years old, he was struck sideways - t-boned - by a runaway ATV moving half the legal freeway speed limit. Launched 20 feet down an embankment.

The owner had failed to set the brake. But I had failed to protect my son.

This is the terriblest day ever," he said between moans. "Am I going to die?"

"No you are not!" I stated with conviction that betrayed my concern. "I will not let that happen."

After cutting his clothes and gear to ribbons and summoning an ambulance from the nearest town up the trail, the rangers believed my boy had suffered only a broken leg. Still, they braced his neck and took great care in getting him on the gurney.

Just a couple of hours, but more screams than I care to recount, later he was in a partial cast and better spirits. With any luck, he'll be running in three or four months. But the trauma may last much longer.

And I have no one to blame but myself. Sure, the owner of the mishandled four-wheeler is culpable, but she doesn't owe him safe passage.

That is my job and one I thought I accomplished. He was wearing every bit of protective gear on the market. I ride behind him wherever he goes to fend off possible collisions caused by overzealous riders blazing by my wobbling son.

That's why I was at the back of the pack yesterday, forever aware of the dangers of fast-moving machines and my slow-going boy. But that left me one spot away from him, riding single file between two good friends, a married couple.

I was checking traffic before and aft when the gray 500-pound contraption emerged from the brush heading straight across our trail on its descent to the valley. I had time to shout "Go!" And nothing more.

Dropping my bike, I ran down the hill and held him. I didn't know how bad, but I knew he was hurt. My friends gathered help. The responsible parties grieved. And... here we are.

It was a parental nightmare, the kind you dread and then appreciate waking from. But last night, I woke up nearly a dozen times unable to shake this state. It's real.

And I'll always wonder if I could have saved him this.