Here comes underwater action for the young Armouron knights! A select group of Gladiators are 'on tour'. First stop is a bizarre floating city called Drift City. Salt, as armourer, manges to bring his four young Armouron knights with him as 'assistants'. But all is not well in Drift City. People have gone missing. And what is in the cargo containers being unloaded at night into hi-tech subs? Why are these subs guarded by robots? As the Armouron Knights dive underwater to discover the truth, they uncover a terrible plot - a plot that could lead to many lives being lost if they don't act very quickly...