This story is told by Reb Zalman in his book
Jewish With Feeling, Pgs 69-72. With ease, I can hear my rebbe’s voice telling it to me.

One day the Baal Shem Tov sits at his table with his people. The weather is getting cold, but he says, “Get the wagon together, and make sure you bring some lekach and some bronfen (cake and spirits), and come with me.” So they get into the wagon, and after a time they come to an inn. The Baal Shem says to the innkeeper, “Can you prepare for a wedding?”
And the innkeeper says, “Yes, of course. How many people?”
“Not too many people, “the Baal Shem replied, “but we’ll need a nice meal.”
“No problem,” the innkeeper says, “I’ll send over to another fellow who has a roadhouse a little further on, so he and his wife can come and help. I’m a little short-staffed right now,” he explains. “I usually have a young woman and a young man here to help me, but they’re off today, the two of them.”
“Where did they go?” the Baal Shem says.
“Well, they’re about to get married, and today they went to the town to buy what they need for their new home together. They’ve been saving up for years.”
“Very good,” the Baal Shem says, “All right, start preparing.”
Meanwhile, the young couple are on their way to town. No sooner do they get to the market when they see a family being dragged through the streets in chains. The town crier shouts in front of them, “These people haven’t paid their rent to the landlord! They are going to be put into the darkest jail until they rot there and die!”
The couple are appalled. “How much do they owe?” they ask the town crier.
“Three hundred rubles,” he says.
Three hundred rubles! It is all they have. But he looks at her and she looks at him, and yes, they take off their money belts and give everything they have to redeem the family. Before the family have even recovered enough to thank them, the couple are gone.
On their way back they agree: “We can’t tell the people that we gave away all our hard-earned money: they’ll call us fools! Let’s rough each other up a little, and when we get back we’ll say that robbers fell on us and took our money.”
So they came back bruised and empty-handed to find the inn in an uproar, preparing for a wedding as the Baal Shem had requested. The innkeeper rushes up and says, “Good, you’re here! Quick, I need help setting up – oy, vey, what happened to you? Where’s the furniture?” And they tell him the whole tale of woe.
At this, the Baal Shem calls them both aside and says, “It’s your wedding that we’re preparing for, and I am here to marry you myself.” And so they were married.
Now it was the custom that the guests at a wedding would say a droshe geshank, a little speech announcing the present that each guest is giving to the couple. “I give a pair of handsome brass candlesticks,” one of the innkeepers says. “I’m going to give a baking trough,” says another. At some point they return to the Baal Shem. “What about you, Rabbi?”
And the Baal Shem says, “To the groom I give the estate of Count Potptzki. To the bride, I give Countess Potozki’s jewelry.”
All the guests laugh uproariously and they continue with their meal and the seven traditional blessings.
Suddenly before dessert is on the table, the Baal Shem says to the couple, “You must leave now, right away. Get on your wagon and horse and go.”
“Where should we go?”
“Into the forest. Go.”
In the meantime a snowstorm has started, a blizzard. The couple are in the middle of the forest and lose their way. All of a sudden, the horse rears up and refuses to go a step farther, When they peer ahead to see what the problem is, they see the body of a young boy lying in the snow. They dismount quickly and pick him up. He’s still alive, and they rub him all over and give him some schnapps and the lekach that the Baal Shem Tov gave them for the way.
“Who are you?” they ask the boy. “Where are your parents?”
“I am the son of the Count and Countess Potozki,” the boy tells them. I received a new horse for my birthday, but the horse threw me off and I don’t remember anything after that.” And he points them to the castle of the Count.
Meanwhile, the Count and his wife are beside themselves with worry. The horse they’d bought for their son had returned without its rider. The Count’s followers had been unable to find the boy in the worsening storm, and the weather was getting so bad that they were afraid to continue. Finally, in desperation, the count said, “I pledge my entire estate to the person who brings back my son.”
“And I pledge my jewelry as well!” says the countess.
Just then the couple arrives with the boy on their horse. And that’s how the Baal Shem’s drosha geshank to that couple, who had given all their money away to redeem a captive family, came to pass.

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In the book, Reb Zalman tells us that this is an example of a good story for a melaveh malka, a post-Shabbas Saturday night gathering. Why? Because he explains that “embedded in these tales was the message that any one of us, with no warning or preparation, may be presented with the opportunity to serve as the Holy One’s instrument to improve the world – if we rise to the occasion. This vision, this mystic ideal, this high ambition, is what we take forward with us into the week” (Jewish With Feeling Pg. 74)

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A personal note: When a storyteller follows up a story by telling the listener what it means, my heart sinks and my mind withdraws. In this case, however, I could not resist. It’s a machaya to have been given the sod (secret) from Reb Zalman.