The team start looking for the killer when they realize the murders have been starting after Maria's meals.
At the UFO Emporium, Max and Michael find themselves kidnapped. Maria is acting sketcy, and Cameron and Liz realize she has been drugged, presumably by the fourth alien.
It emerges that Noah is in the frame and everyone starts to question the theory.
Liz rushes to find out the truth via a blood sample from when he was shot. This confirmed everything and she attacked him when he tried to hurt Isobel.
Maria was put on the spot but ultimately realized that she was fine following the latest violence.
Isobel was crushed when Noah would not say he loved her and that he loved Rosa more.
Liz tried to get her father to agree to go the legal route to become a resident of the U.S. and he later agreed because he had someone on the inside who could help ... Noah.