A scientist in yellow overalls is taking samples of green algae on a beach in Brittany. Lifting his mask, he suddenly drops down dead. There’s panic in the village – he’s not the first person to disappear, and the municipality suspects that toxic algae are the cause. Nevertheless, it’s out of the question to endanger the tourism industry or accuse intensive farming for this maleficent bloom. The mayor prefers to suspect the Parisian “bobos” who rent the Airbnb on the beach. But all it takes is one high tide for the dead to re-emerge from the seaweed carpet as zombies.