After their chilling encounter in Transylvania, Anna and Max just want to stay out of trouble, but trouble has other plans. Their father, the Professor, has taken them to the cold and foggy fields of England, where a new mystery is afoot. A small boy has disappeared near a strange and mysterious river, lost without a trace and Anna and Max join the search to find him. But as the river's sinister secret is revealed, can the siblings save the missing boy and themselves?
