Mabel Hartley has her heart set on New York City and finding treasure in the Catskill Mountains left by gangster Dutch Schultz in the 1930s. Welcomed by Jules, Mabel's roommate from Jordan, they set out to discover if their luck will hold. But first Mabel makes a sinister visit to her birth mother in prison and receives an ominous warning that she cannot shake free.
Hugh and Mabel have never been more distant and cannot find their way back to each other. Barnaby Mason, Tabby's old brother is keen to join the treasure hunting team and have Mabel for his own. That is if Mabel can give her heart to someone other than Hugh. Adventure beckons but not all the teens will make it back to the UK. Danger lurks and Mabel's life has never been more in jeopardy.