Albert Uderzo Asterix and the secret weapon

A woman bard in Ancient Gaul? A shocking idea, but that's what the Gauls get when the mothers in Asterix's village hire Bravura to teach their children.

Although she, Asterix and Obelix are unlikely allies, between them they fight back against Julius Caesar's secret weapon.

What can that weapon be? And how can even Cacofonix help?.