Buck and Wilma discover that Kaleel, a demagogue with strange powers, plans to destroy the Earth with his own small fleet of spacecraft. Normally such a plan would be pure folly, but Kaleel has incapacitated most of Earth's defense force with poisoned food. However, Kaleel's own forces have a crucial weakness that Buck believes he can exploit to defeat them, even with a handful of barely capable flies of his own.

Some time ago, Earth Defense Directorate agents killed Morgan Deneva, a member of the deadly Legion of Death. These assassins have sworn revenge, and with their brains and unusual abilities, they might well manage it. So Buck goes undercover as Raphael Argus, a killer whom the Legion was on the cusp of inducting, but whose face is unfamiliar to them. His job is to infiltrate them and learn what they're planning. But they have a spy in the Directorate whose inside information might end Buck's imposture rather... abruptly...