Yoko Tsuno Vol. 9: The Forge of Vulcan

Yoko returns to the alien world underneath our own. A strange accident at an offshore platform in the Caribbean draws Yoko, Vic and Pol into a new encounter with the Vineans - aliens who have lived underground for thousands of years without the world's knowledge. But Vinean politics are changing; some factions now believe it would be best to return to the surface, share it with the humans...while others are bent on taking it over by force. The young Japanese will have to fight to protect peace.