Jamie, Davies, and Ten Tons are mudlarks, boys who stay alive in 1850s London by finding and selling coal in the banks along the Thames River. Their dream is to find adventure by going to sea, but they"ll never get a place on a seagoing ship without the money to buy an apprenticeship. Then they spot a potential treasure -- a half-ton of copper. All they have to do is rescue it from the depths of the river....