A hiker is being pursued by... something... in a cave in the woods, and Lauréne is out jogging in the forest when she hears the commotion. Everyone seems to- Cora (her daughter) is at archery lessons and hears it, and Sabine senses something (early foreshadowing that Sabine is connected to whatever lives in the woods). The hiker makes it out but his girlfriend Nathalie is still in the cave somewheres.
Steiner, meanwhile, has his website defaced by graffiti- apparently the work of an environmental group- their symbol is one Cora's been encountering around the town. Our new DA has a conversation with Sabine, and Fire Rescue finds no trace of the missing Nathalie. Cora is researching the symbol and finds Celtic and Norse connections. She also finds out the cave was used for Celtic burials...and finds a reference to Arduinna, an ancient Celtic goddess of woodlands.
Siriani wants to know if Lauréne is in with the Steiners, and a Steiner thug lets on that there really was a Nathalie- or someone- after it appears initially that there was no such girl at all. Lauréne and Teddy Bear go spelunking while Cora discovers that a eco-terror group named The Children of Arduinna are in Villefranche now to fight the Steiners. And... she's being hacked...
Don't wander alone in caves.
So... they're hallucinating. Must be strange gases down there. And Lauréne thinks she finds the missing girl, but they just find a pack... and some clues. It was a con, the missing girl was a grifter and she meets a rather... yucky ending. Hanging with the crows... Later Teddy speculates that the moss or something might be hallucinogenic, and the doc says the land is rebelling or something. Hm... and Sabine tells Lauréne she'll have to choose sides at some point.