The Lion, the Fox, and the Stag explained simply

A Lion lay sick in his den, unable to provide himself with food. So he said to his friend the Fox, who came to ask how he did, "My good friend, I wish you would go to yonder wood and beguile the big Stag, who lives there, to come to my den: I have a fancy to make my dinner off a stag's heart and brains." The Fox went to the wood and found the Stag and said to him, "My dear sir, you're in luck. You know the Lion, our King: well, he's at the point of death, and has appointed you his successor to rule over the beasts. I hope you won't forget that I was the first to bring you the good news. And now I must be going back to him; and, if you take my advice, you'll come too and be with him at the last." The Stag was highly flattered, and followed the Fox to the Lion's den, suspecting nothing. No sooner had he got inside than the Lion sprang upon him, but he misjudged his spring, and the Stag got away with only his ears torn, and returned as fast as he could to the shelter of the wood. The Fox was much mortified, and the Lion, too, was dreadfully disappointed, for he was getting very hungry in spite of his illness. So he begged the Fox to have another try at coaxing the Stag to his den. "It'll be almost impossible this time," said the Fox, "but I'll try"; and off he went to the wood a second time, and found the Stag resting and trying to recover from his fright. As soon as he saw the Fox he cried, "You scoundrel, what do you mean by trying to lure me to my death like that? Take yourself off, or I'll do you to death with my horns." But the Fox was entirely shameless. "What a coward you were," said he; "surely you didn't think the Lion meant any harm? Why, he was only going to whisper some royal secrets into your ear when you went off like a scared rabbit. You have rather disgusted him, and I'm not sure he won't make the wolf King instead, unless you come back at once and show you've got some spirit. I promise you he won't hurt you, and I will be your faithful servant." The Stag was foolish enough to be persuaded to return, and this time the Lion made no mistake, but overpowered him, and feasted right royally upon his carcase. The Fox, meanwhile, watched his chance and, when the Lion wasn't looking, filched away the brains to reward him for his trouble. Presently the Lion began searching for them, of course without success: and the Fox, who was watching him, said, "I don't think it's much use your looking for the brains: a creature who twice walked into a Lion's den can't have got any."