In 1884 London, 12-year-old Albert Gladwyck must decide whether to follow his generous heart or learn to harden it in the harsh world in which he lives. As a River Thames scavenger, he has made the find of a lifetime, a wrecked boat full of goods, washed up on the Isle of Dogs and hidden from view. To save himself and his Mum from severe poverty, he must try to make salvage from the wreck before the other mudlarks find it, before the bully, George Hardly, catches up to him, before illness and death from the poisonous river have a say in the matter.