A man left to go help in the Crusades and decided that his wife should wear a chastity belt. So he locks her up and gives the key to his best friend.
He tells him "If I'm not back in four years, unlock my wife and set her free to live a normal life."
So, the husband leaves on horseback and about a half hour later, he sees a cloud of dust behind him. He waits for it to come closer and sees his best friend. "What's wrong?" he asks.
▼Today's Expression
set her free "set ~ free"で~を逃がす、~を自由にするという意味ですね。"Set free"では 逃がすという意味になりますが、"Let free"では「離す」という意味になります。