Three gunrunners are killed by a new high-tech weapon called "The Vaporizer." And after Horatio interviews the CEO of the defense contractor that made the weapon, he also turns up dead.

A billionaire is murdered in his Miami home just before he can sign an important legal document. When Horatio arrives on the scene, he's shocked to discover that the victim's widow is his former lover and Kyle's mother. She is also a leading suspect in her husband's homicide. In court, Kyle goes on trial for kidnapping and his mother makes it clear she will do anything to regain custody of him.