The son of a prominent New England industrialist has been kidnapped. Erskine's investigation is complicated when the father receives two ransom notes. One is genuine, the other a "satellite," an extortion demand by someone not actually involved in the kidnapping. Erskine believes the second ransom note is the real article; its phrasing points to a younger person. But the FBI must cover both ransom drops. Meanwhile, the real kidnapper grows more volatile, endangering the life of the kidnap victim.