A farmer left his plowshare with a merchant friend while he traveled.
"I'll keep it safe for you," the merchant promised.
When the farmer returned, the merchant explained that the farmer's plowshare had disappeared. “The mice must have eaten it," he said.
“Mice can’t eat iron!” retorted the farmer, but the merchant swore it was true.
The farmer then kidnapped the merchant’s son.
“Where’s my son?” the merchant asked.
“An eagle carried him off.”
“An eagle couldn’t do that!”
“No more than mice can eat iron.”
Thus the merchant returned the farmer’s plowshare, and the farmer returned the merchant's son.
Inspired by: The Jataka, translated by W.H.D. Rouse.
Notes: This is the Kuta-Vanija Jataka, and it also appears in the Panchatantra, Book 1, Story 31. You can find different versions of this folktale type here: The Iron-Eating Mice.
Here is an illustration by Grandville for La Fontaine's version: