As Molly works to create a virus that will eradicate alien hybrids, she discovers that aliens are trying to communicate with humans through a hidden message in their DNA. Also, Lucy helps Ethan run away from Charlie in order to help him recover memories of his mother, Molly.

Molly starts changing physically, but isn't sure of the result or if she can reverse it, which sends her into a panic. Also, JD's ex-wife reappears to discuss their daughter. Later, Molly and JD hope for peace and try to get Shepherd to broker a deal between humans and hybrids, while Lucy tries to manipulate Charlie's feelings to put him in a compromising position.