Gregory knew enough about his Uncle Dittlemore to expect something unusual from him for his sixth birthday. But that was not enough for him to unwrap his package and find a large rusty key inside the box. Since Gregory had no idea what the key was for, or even how he could use it as a toy, he did not know what to say. Fortunately, his mother had told him twenty times the day before that he should say "thank you" to Uncle Dittlemore no matter what he gave him, so Gregory knew enough to say "thank you." Uncle Dittlemore, who looked as strange as his name, winked at Gregory as if he were enjoying a private joke. However, Uncle Dittlemore showed no sign that he was going to explain the present or anything else.

Gregory's mother and father looked every bit as puzzled as Gregory felt. All they could do was shrug their shoulders and say how nice it was for Uncle Dittlemore to come over for breakfast and bring such a handsome rusted key. Gregory's older brother, Edward, laughed when it was his turn to look at they key, but it was a good-natured laugh, and Uncle Dittlemore did not appear to be offended by it. Gregory's sisters, Lucy and Linda, did not laugh at the key. They were curious about it and they asked many questions that Uncle Dittlemore did not answer very satisfactorily. After hearing his sisters ask so many questions, Gregory decided to ask one of his own.

"What door does this key open?"

"I was wondering when you would ask that," Uncle Dittlemore replied. "The answer is: I don't know. There is no telling which door it will open or what you will find on the other side of the door when you open it with this key. If you wish to know which door it opens, you will just have to try every keyhole that interests you until you find the keyhole that fits the key, in which case the key will fit the keyhole as well. Then, if you are really curious and adventurous and want to have the best birthday present you will ever have, you can open the door."

With that piece of advice, Gregory took the key and ran from the table to look for doors with keyholes in them. First, he tried the front door, but that did not fit at all. Second, he tried the back door but with no better luck. Then, he went from room to room. But every keyhole was either too big or too small. If Gregory had looked at a clock, he would have known that he had spent about five minutes looking for the right keyhole, but Gregory thought he had been looking in vain for ages. When the key did not even fit the door of his own room, Gregory was ready to give up. He pounced on his bed and pounded the mattress. But then Gregory remembered that he hadn't tried his closet door yet. So Gregory stopped pounding his mattress, ran over to his closet, and put the key in the keyhole. The key fit! Gregory hesitated for a few seconds. Then he was ready to find the best birthday present he would ever get. He opened the door and stepped into the middle of a wild forest.

When Gregory looked about in this forest, he rather doubted that he would find his best birthday present after all. A forest may be beautiful with its trees and wildflowers, but when it is so dark that one has to worry about strange beasts lurking in the shadows, one thinks more of being scared than about the forest's beauty, and that is exactly what Gregory was thinking about. Every rustling in the undergrowth made Gregory want to run back to his own room and stay there. But Gregory did not want to give up finding his best birthday present just yet, although he had no idea what he could find in this forest. He hoped Uncle Dittlemore knew what he was doing when he gave Gregory the key to this forest, but Gregory was afraid his uncle might not know and that Gregory was on his own.

Gregory looked between the trees that were so thick and high they blocked the sun. He kept an eye out for wild beasts, but he looked for whatever else might be on the ground or in the trees. As he looked, Gregory saw something. What Gregory saw was a white baby animal lying all alone on a pile of dead leaves. The animal looked like a baby horse, only it was so small that Gregory could hold it in his arms. Not only was the horse white, it had a golden horn growing out of its forehead. It was a baby unicorn! All around the unicorn there was a pool of blood, but when Gregory looked carefully, it appeared that the unicorn itself was not bleeding. It was, however, shaking with fright. Since Gregory assumed everybody has a mother, he assumed the unicorn did too. But where was she? Gregory asked himself. Perhaps a wild animal or a wicked hunter had killed her and dragged her away, leaving the baby unicorn to die all alone.

Never had Gregory seen anything so helpless. The baby unicorn's legs were so thin, it would not be able to stand on its own, just as human babies can't walk at first. There was no milk or baby food around so there was no way the unicorn could feed itself. If another wild animal or wicked hunter came along, looking for another victim, the unicorn would not be able to flee or defend itself in any way. Gregory was the kind of person who knew that if he should be as helpless as this unicorn, he would want to be picked up and fed and defended. There was no time to waste. Every rustling sound in the forest reminded Gregory that danger could be lurking anywhere, at any time. Gregory whisked the unicorn up in his arms, but just as quickly, the unicorn thrashed in every direction, scratched Gregory on the cheek with its tiny horn, and jumped back onto the leaves.

"If that's the way you feel about it when I'm trying to help," said Gregory, "then you can stay here all alone and take care of yourself."

Gregory walked away in a pout, all the while rubbing his scratch. Fortunately, the horn was not long enough and hard enough to hurt Gregory very much, but it did hurt and Gregory did not like that. As soon as his back was turned, Gregory heard such a forlorn cry that he turned around. The poor unicorn was crying for its mother. Gregory did not blame it, for he would do the same thing in its place. There was no way Gregory could explain that is mother was never coming back, but there was something he could do. Now Gregory understood that the baby unicorn had thrashed about in his arms and scratched him because it was scared. It was scared of being all alone, and it was scared of strangers. After all, Gregory thought, he was afraid of strangers, too.

Gregory stooped down to the unicorn and started to make friends with it more gradually. He petted the baby animal on the back very gently. When the unicorn realized it wasn't being hurt after all, it stopped shaking so much and it didn't cry out as loudly. Gregory spoke gently, knowing that the unicorn probably did not understand him but it would respond to the tone of his voice. Before very long, the unicorn was licking his hand. For the second time, Gregory picked up the unicorn and held it in his arms, only this time he did much more slowly and carefully. For its part, the unicorn lay quietly against Gregory's chest and nuzzled its horn against his cheek so that it tickled, but did not scratch.

By this time, Gregory was thinking it was time to take the unicorn back to his house. He looked for his closet door and found the rusted key sticking out of a nearby tree trunk. He freed a hand just enough so that he could turn the key. A door opened out of the tree and Gregory stepped out of his closet and into his bedroom.

With the bellowing unicorn still in his arms, Gregory ran downstairs to the kitchen were everybody was still at the breakfast table. His family was amazed to see the baby unicorn in his arms.

"So that's what you've found!" exclaimed Uncle Dittlemore.

"How can we ever have a pet unicorn in the house?" asked Father, looking none too pleased.

"The same way anybody else has a pet unicorn in his house," Edward answered.

"Which nobody does," Father growled.

"We'd better give it some milk," said Lucy as she opened the refrigerator door.

"We can use the cat bowl," Linda suggested as she took the milk out of the refrigerator.

"If we have to give it milk, I'd better heat it first," said Mother. "It's just like the way I heated the milk I fed you kids when you were babies."

"Does it need a baby bottle?" asked Lucy.

"Well, yes, it does," said Mother.

Linda found a baby bottle in one of the cupboards and washed it out so that it was ready as soon as the milk Mother was heating on the stove was ready.

"But as soon as we feed the unicorn," said Mother, "we'll have to give it away."

"How can we do that?" asked Gregory in alarm. "Who can we give it to? Who else wants a unicorn?"

"I suppose you think you can just put an ad in the paper advertizing a baby unicorn," said Edward rather sarcastically.

"But what will the neighbors say?" asked Mother.

"Let them say anything they want as long as I can keep my baby unicorn," said Gregory.

Mother took the sauce pan off the burner, poured the milk into the bottle and handed the bottle to Gregory. The baby unicorn sucked at it desperately and gratefully.

"Gregory, you have to understand one thing," said Father. "This world is just not made for unicorns. That is why you can't keep it."

"Then we'll have to make the world for unicorns," said Gregory. "Otherwise, it will die."

"That is quite a cogent argument," said Uncle Dittlemore.

Gregory did not understand the word, but he could tell by the way Uncle Dittlemore looked at him that his uncle was supporting him all the way.

"If we make the world a good place for unicorns," said Lucy, "then maybe other people will think it's a good idea."

"Then they will make the world a good place for unicorns, too," added Linda.

"And then maybe everybody will think the world is a good place for unicorns," said Edward.

"Dream on," said Father.

"Daddy! Mommy! Edward! Lucy! Linda! Uncle Dittlemore!" Gregory cried.

"What is it?" everybody asked.

"The baby unicorn just told me his name!"

"How can a unicorn to that?" asked Mother unicorns don't talk.

"Well unicorns can think, then," said Gregory, "because it just thought that his name is Calibur and so I thought it, too."

"You must be imagining things," said Father.

"So? Even if I imagined it, it's true. His name is Calibur. So we have to keep him."

And Gregory and everybody else in the family knew that they would do just that.