When her scientist ex-boyfriend discovers a portal to travel through time -- and brings back a 19th-century nobleman named Leopold to prove it -- a skeptical Kate reluctantly takes responsibility for showing Leopold the 21st century. The more time Kate spends with Leopold, the harder she falls for him. But if he doesn't return to his own time, his absence will forever alter history.

In the rail yards of Queens, contractors repair and rebuild the city's subway cars. These contracts are lucrative, so graft and corruption are rife. When Leo Handler gets out of prison, he finds his aunt married to Frank Olchin, one of the big contractors; he's battling with a minority-owned firm for contracts.

A mathematical genius discovers a link between numbers and reality, and thus believes he can predict the future.