 Convinced that his grandfather was right and that the Kingdom may be prospective for oil, the race is on to prove that there is oil under Campbell's Kingdom before the mining company building the dam can flood the valley.Standing in his way is corrupt construction contractor Owen Morgan (Stanley Baker), who resorts to dirty tricks in order to prevent Campbell from succeeding in his quest.However, Bruce is ably and enthusiastically assisted by love interest Jean Lucas (Barbara Murray), geologist Boy Bladen (Michael Craig) and drilling contractor James MacDonald (James Robertson Justice).