Cassy and Jonas make an extraordinary couple with an unusual need - human hearts. With no ties, family or friends, never settling, they head forwards on their eternal journey round the world. While making the crossing from the United States to Europe, unbeknown to Jonas his latest victim emails a recording of his own death to his computer at home. The couple travel to London, where they seek out an old friend but discover disturbing details about his life. Federal Agent Wheeler picks up a case which fits into a pattern he's working on, but the more he searches, the worse it gets and the more...