The Garden of Youth (or simply, the Garden) was an isolated orchard, enclosed by high walls of green turf, which was broken by a single pair of high solid, golden gates that faced due east.
On the gates, in letters of silver, were written the words: -
- Come in by the gold gates or not at all,
- Take of my fruit for others or forbear,
- For those who steal or those who climb my wall
- Shall find their heart's desire and find despair.
This was actually a warning to all not to pluck and eat the Garden's apples, but to, instead, take them to feed or help others.
Much about the Garden remains a mystery, especially the fact that it was only ever known to be explored in Narnian-year 1, and was otherwise absent throughout the rest of Narnia's history. All that was known that it was a happy, but very serious, very quiet place - "even the fountain which rose near the middle of the garden made only the faintest sound", and that the leaves of the trees "showed not only green but also blue and silver when the wind stirred them". There was also a most lovely smell all about the Garden, described as "warm and golden, as if from all the most delicious fruits and flowers of the world".
The only two people known to ever visit the Garden were Digory Kirke from Earth, and Jadis from Charn. Each plucked an apple from the Tree of Youth; Jadis took the fruit and ate it for personal gain, while Digory, on the other hand, took it only at the request of Aslan.
By doing so, Digory was forced to face two devastating temptations: First, he very much wanted to eat it himself the instant he looked at it and smelt it - "A terrible thirst and hunger came over him and a longing to taste that fruit". The second temptation, he learned, was that he could use the fruit to save his gravely ill mother's life.
Very fortunately, Digory was able to resist both temptations, and by doing so he saved both himself and his mother from terrible fates that would have taken place if he had succumbed to either one of the temptations, given that the fruit will not work happily for those who pluck it at their own will.
Jadis, on the other hand, had actually doomed herself: The fruit she ate did indeed grant her her heart's desire of being immortal and having inexhaustible strength, but it also brought her despair, given that she would always be miserable and never happy. And because she was immortal, that meant that her constant misery would never end.
The apple that Digory plucked was later planted near the river bank, where the ground was soft, and it grew into a magnificent adult tree in only a matter of minutes. Aslan stated that this tree would prevent the return of Jadis as long as it flourished, later named the Tree of Protection.
This was also where the true story of the real Narnia had begun.