Astrid and Raphaëlle find out that the dead body discovered after the collapse of an underground gallery is that of an 80 year-old alchemist.

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.

After the president of an autistic association dies mysteriously, a new corpse is found. Though officially deceased days earlier, he is a suspect.