Fourteen-year-old twins Joanna and Samuel Clark of London, England, were invited to join their friend Gareth Morgan and his parents for what promised to be a fun, weeklong vacation in New York City. But no sooner have they embarked on their first sightseeing tour than the twins find themselves being chased through Penn Station by four mysterious men. Narrowly escaping their pursuers, Joanna and Samuel happily reunite with Gareth, only to be swept up into far more harrowing adventures across the city.

Aided by a pair of well-connected private detectives and clues embedded in Joanna's "vision-dreams," the twins and Gareth discover that the same enemies who attempted to murder them in the Welsh forest less than a month earlier have returned. Only now, the stakes are higher: these sinister forces are plotting to deceive — and potentially harm — millions of people around the world.

Against this backdrop of international intrigue and danger, the special relationship between Joanna and Gareth that began to develop in The Visioners: Into the Wilderness is severely tested. Will the teens, who were just starting out on the exciting and awkward path of getting to know each other better, be separated forever?