Spirou and Fantasio decided, accompanied by the Marsupilami and the spip, to visit the Count of Champignac, on the occasion of the bestial fair! But there, surprise!!!! The old vermoluous door of the castle has left room for an armored door. A little confused, they still manage, thanks to the Marsupilami, to break in. The atmosphere is heavy during the evening. Champignac is different, and Fantasio flirts with a mystery!! He will soon discover its nature. It presents itself after a brutal encounter, in the form of a Confrerere of Champignac, INOVSKYEV. The reason why Champignac had wished to hide its host, comes from the fact that he holds a brilliant weapon, the gag, sought by several peoples. Moreover, some Russians seem to be already roving in the village. More serious, a confratern of the Russian scientist is locked in a Buddha in Asia. The guards wish to store the information necessary for the making of a GAG, but not a GAG, because it would be difficult to do this, and it would be a disaster-proof operation.