From the publisher:

Does Cibola, the mythical city of gold exist? No geographer can locate it, no conquistador has returned from there, not even the legendary Cuchillo, companion of Cortés. But you, reader, thanks to Toppi's help you have this incredible chance, you will reach Cibola! You will of course have to pay the price and drink the plant that makes you lose your memory, the red sap of the nopatli that colors the magician Toppi's inkwell with blood.

Resume:

Cibola, la mythique cit de l'or existe-t-elle Nul gographe ne peut la situer, aucun conquistador n en est revenu, pas mme le lgendaire Cuchillo, compagnon de Corts. Mais toi, lecteur, grce au concours de Toppi tu as cette chance inoue, tu parviendras Cibola ! Il te faudra bien sr en payer le prix et boire la plante qui fait perdre la mmoire, le suc rouge du nopatli qui colore de sang l'encrier du magicien Toppi.