Mad Jack Halloran's wife, Sarah, has a problem. Jack won't give his treasure back. (Apparently, giving his treasure back will be good for his soul.) She has tried persuading him but he won't listen. Unfortunately, Jack can be very stubborn when it comes to matters of returning treasure. Persuading Jack to part with his treasure isn't the tough bit though; finding it is. Even he doesn't know where it is. How do you find a treasure when you don't know where it is? Can Lucy help him find it? Will he let her? Come to that, how do you give a ghost back his treasure and who does he give it back to? The Treasure of Mad Jack Halloran is the third Mad Jack Halloran book for 10-12 year olds.