When a man collapses on a bus, possibly killed by an extremely contagious disease, the duo ends up confronting the leader of an eco-terrorist group.

At an auction, the auctioneer presents a precious ancient manuscript, the Corpus Hermeticum, before having a fit of delirium and then collapsing, dead. Apparently, he was poisoned, and in panic, the priceless book was replaced by a fake. Astrid and Raphaëlle will be interested in this object that would contain absolute knowledge and that arouses the wildest desires.