Map-obsessed Thomas spends his days and nights on a virtual tour of the world, believing he must store the details of every town and city in his head. Then one day, he sees something that shouldn't be there: a woman being murdered behind a window on a New York street.

When Thomas tells his brother Ray what he has witnessed, Ray humours him with a half-hearted investigation - until he realises Thomas may have stumbled on to a deadly conspiracy, which puts them both in danger ...