Yoko Tsuno Vol. 18: The Rhine Gold

While visiting her friend Ingrid in Koln, Yoko finds herself thrust in the middle of a mystery when a young Japanese woman is attacked in the cathedral, and whispers a few words before passing out - notably ''Rheingold'', the German name of a Wagner opera. Having decided to investigate, Yoko finds signs that the victim had probably set an explosive charge somewhere, and discovers that ''Rheingold'' is also the name of... a very special train!