Act I
Tempted by some warm moss, a forester has fallen asleep in the woods. A little fox cub sets off to investigate the forest, for there are so many strange things out there to discover. A tiny green frog wakes up the sleeping forester, who catches the little fox cub. She calls out for her mother, but the forester is already carrying her back to his lodge.
The little fox cub has grown up to become the vixen Sharp-Ears. She lives in the courtyard together with the dog Lapák, a flock of hens and a cockerel. It is springtime and Lapák is dreaming of love, but to no avail. Sharp-Ears has no experience of love either, though she still remembers what went on in the starling’s nest above her old den. When the forester’s son Pepík shows off to Frantík by poking Sharp-Ears with a stick, the vixen bites him in the leg. A fox is no dog, after all. The forester’s wife makes a scene and Sharp-Ears has to be tied up. The hens are happy – no more being chased around the courtyard, and the vixen has got its just deserts.
Sharp-Ears makes a revolutionary speech, appealing to the hens to overthrow the cockerel’s rule. When that doesn’t work, she pretends to be dead. Nudged into action by the hens, the cockerel goes to check if the vixen has really passed away. One bite later, and the cockerel’s head is in the vixen’s mouth. But why stop at one cockerel when there are so many tasty hens around? The forester’s wife hurries to the yard to find out what all the fuss is about and nearly has a heart attack when she sees the chaotic scene. She yells out to her husband to shoot the vixen but Sharp-Ears is too quick and disappears into the forest.
Act II
Sharp-Ears has found freedom among the trees, but she also needs somewhere to live. Without hesitation, she expels a grumpy old badger from his den, much to the amusement of the other woodland animals.
The forester, a pastor and a schoolmaster drink at Mr Pásek’s pub. The forester teases the schoolmaster for being too scared to proclaim his feelings for his secret love. In reply, the forester is asked a biting question as to how he’s getting on with that vixen he brought home. He growls that she ran away and that he won’t be looking for her. Inebriated, the schoolmaster gets up to go. The pastor follows him, for he has to pack to leave for another parish. The forester would love to tarry a while longer in the company of his old friends, but when his attempts to convince them to stay fall on deaf ears he also heads for home through the forest.
The drunken schoolmaster weaves his way home thinking about his beloved Terynka and stumbles after an apparition. The mind of the pastor, who is also well in his cups, is invaded by thoughts of how a lost love once hurt him. She was beautiful, eyes as deep as a well, and so all the worse was her betrayal. Both schoolmaster and pastor fall asleep in the quiet of the forest. The forester is also there, and when he catches a glimpse of the vixen, he decides to take a pot shot at her. The only thing he almost manages to hit is the terrified schoolmaster, who rushes to get out of the rifle’s range.
One night, in the glade where Sharp-Ears goes on her nightly wanders, who should appear but a fox named Gold-Spur. He’s a good-looking youth and the vixen can’t keep her eyes off him. They shyly get acquainted and Sharp-Ears tells him about her childhood at the forester’s lodge. Gold-Spur disappears, only to return quickly with a gift in the form of a rabbit. Sharp-Ears is bashful at first, but Gold-Spur’s sincere declaration of love wins her over.
The forest has a new scandal, and the owl’s eyes almost fell out when she was telling everyone. Sharp-Ears informs Gold-Spur that their love has not been without consequence – there’s nothing else for it but to go to see the pastor. The woodpecker marries the two foxes and the whole forest celebrates the wedding.
Act III
Summer dissolves into the colours of autumn, and these in turn vanish beneath a cloak of snow. But earlier than anyone anticipates, spring returns, and then another summer and autumn. The forester bumps into Harašta in the woods. He has a pack full of poultry but he swears he’s no poacher. The pair spot a dead hare lying in the clearing, and the forester uses it to set a trap for Sharp-Ears. Her family has been growing well and the parents have their hands full keeping an eye on their curious little offspring. The vixen doesn’t fail to spot the dead hare, but she also sees the metal trap that’s lying in wait for her. Harašta sees the vixen’s tail and wants to give it as a pretty gift to his bride-to-be. He grabs a stick and heads after the fox, but the woodland creatures get under his feet and Harašta ends up with a bump on his nose. The cubs take the opportunity to go through his pack of poultry with Sharp-Ears, but suddenly Harašta shoots her.
The patrons at the pub are not in a jolly mood. Pásek has gone to Brno and his wife complains that she has no time to chat with her guests. The pastor is missing, and the schoolmaster is down in the dumps because his secret love is getting married to someone else that very day. The friends part earlier than usual and the forester heads home through the forest once again. Everything reminds him of the day he found the vixen – and then he sees her, the spitting image of her mother. He tries to catch her but is foiled by a tiny green frog, the grandchild of the earlier one. It is as if life stopped for just a second, and a second lasted a whole lifetime. Such is the everlasting circle of life.