The Gardener–Root Rot??
In this six-episode Spanish psychological thriller (now #3 on Netflix), we see two mother-son pairs who are cold-blooded killers. The Gardener (Spanish: El Jardinero) showcases a quiet studious young gardener, Elmer, who lives with his mother, China, owner of a nursery. He has frontal lobe damage from a car accident. Avoiding a fatal end, Elmer and his mother, who was severely injured as well, become inexorably intertwined in a cat-and-mouse game of murder.
China grooms her now adult son to be a contract killer. Having no feelings for his murder victims, Elmer seems...