A white man from Tennessee arrived in the California gold camps with 3 slaves. He put them to work while he rested in town. This didn’t set well with the miners. It wasn’t about whether or not they opposed slavery, they didn’t like the idea of a man loitering in a bar while somebody else dug for his gold. They decided to educate the slaves about the law.
When he came to get his gold the slaves informed him, they were in a free territory and no longer slaves. Therefore he had no right to the products of their labor—unless he was willing to work. He took them to court and lost! The man went back to Tennessee with neither gold, nor slaves.