The story:
The Phantom fears that a 300 year old crime organisation basing its modus operandi on the old legend of Hydra, a mythical monster with nine heads slain by Hercules, has risen from the ashes when an informer is shot but manages to whisper ???Hydra?? in front of a witness before he dies.

Wasting no time, the Phantom begins to investigate the case, but is thwarted at every turn by the organisation's determination to eliminate every trace of its existence. When an opening finally presents itself, the Phantom has no choice but to act like a modern Hercules and enter his adversary's abominable den...