Mike and Martin are on the run and Robin had a baby lizard.
Martin and Mike leap out of the ship, escaping by sky-diving. Meanwhile, the human looking twin has shed her skin and grown to the age of two in a day or two. The lizard twin dies, so Robert, Robin’s father, studies it. That’s what Grandpas are for, after all. He and Julie make a discovery that they think could result in a weapon to use against the Visitors. Julie comes back to find that the baby has shed her skin and apparently walk away. They hear a scream. Robert’s youngest daughter was attacked by her niece who spit venom on her.
On the Visitor Mothership, Diana discovers that Pamela and Steven are forcing her out of Command. Back on earth, the rebels have created their weapon. Ham wants to test it on Willie, but nobody else is willing, because Willie is so sweet. So they go to Daniels and kidnap Brian. You remember Brian right? Got Robin pregnant. Ham wants to kill Daniel for killing Ruby. Caleb states he has a better bit of revenge. He knocks Daniel out and calls the Visitor “helpline”. Steven picks up the phone and Caleb gives an anonymous tip that Daniel set Brian up. This results in Daniel finding out they are going to put him on a serving platter. A just end to a prideful ass.
Back on earth, Robin introduces Brian to Elizabeth, his daughter (who appears to be about four years old). He promises that if she lets him out of the glass cage he is in, they can run away together. But Robin is past her crush. She throws the chemical weapon into the case, which has the desired effect. Brian dies. Father Doyle removes Elizabeth from the room and then Julie gets in the case to see how the chemical impacts humans. Luckily, it has no impact. Father Doyle has taken great risk. He brings young Elizabeth to meet Diana, attempting to be an emissary of peace. He believes this proves that humans and Visitors are more alike than different.
Mike starts to wonder about his son. His son hates baseball now and believes the Fifth Column are traitors. In the meantime, there is an attempt to create a vaccine for the Fifth Columnists to protect them from the toxins. Ham decides to ship the toxin before there is a vaccine. Unlike Mike, he would be happy if the Visitors were completely eradicated. Mike and Ham have a fist fight that more or less just exhausts them, rather than having a winner. But they do agree to wait to ship the toxin.
Meanwhile, Diana is trying to indoctrinate Elizabeth, while “protecting” Father Doyle to keep his confidence. Martin reveals that the ships are giant nuclear devices that the Visitors will use if threatened. What no one realizes that Sean is watching. He’s a spy for Diana. Julie sees him and he tries to sneak away. He pretends he was just looking for his dad, but Julie is not fooled. She tries to tell Mike, but his reaction is bitter, he cannot accept his own son would be on the side of the Visitors.
On the Mothership, Diana has been reading Father Doyle’s Bible. At first he is excited, as she seems interested in discussing it-but it turns out the Bible caused her to see weaknesses in herself, weaknesses she needed to eradicate. And she shoots Doyle. As he lay dying she adds insult by incinerating his Bible.
Ham tells Mike he knows Sean was converted. Mike tests Sean by telling him how much he loves him. Sean is entirely uninterested. Instead, he runs off to his Grandmother Eleanor and tells her and Steven all about the plan. Pamela and Steven laugh off this supposed plan, but Diana believes it is true. She meets with Pamela and revolts, killing Pamela. But the twist is? Pamela was right. The rebels gave Sean false information.
While the Visitors keep watch over military bases, expecting the rebels to steal planes, the rebels are taking the toxin up in hot air balloons and getting aboard Visitor ships to supply toxin there as well. Then they launch an assault on the home of Mike’s parents, occupied by Eleanor and Steven as a Visitor Compound. As it looks like the Visitors are losings, due to the Toxin, Steven begs Eleanor to run out and tell them he surrenders, or anything that will save him. She runs out yelling for the rebels not to shoot. She announces she is one of them, and declares Steven, their “leader,” is inside and has been holding her prisoner. She is repaid for her treachery with a laser blast in the back, killing her. Steven runs back inside, but it is to late. Ham catches him and force feeds Steven the toxin, killing him rather quickly.
Up on the ship they start launching the toxin through the ventilation system. But a firefight breaks out, disrupting the plan. Harmony is shot protecting Willie, who in turn is unwilling to leave her side. Honestly, of all the relationships this series worked to sell? This was the sweetest and by far the most effective. The two rebel groups on the mothership are pinned down, prevented from finishing their mission.
On the ground, the rebels celebrate their victory. But Ham is wondering how long the victory will last. Up in the mothership, Caleb suddenly rushes grabbing the hose and spraying the soldiers with the Toxin, allowing them to continue spreading the toxin through the ventilation. This kills the guards that have pinned the second team, allowing them to proceed.
Diana realizes that the airfields were a diversion, and that the balloons they are witnessing are the real way the toxin is being dispersed. John scoffs, noting that there is not enough balloons to do that much damage. But Diana is a scientist and understands…all the toxin has to do is get into the food and water and as bacteria it will grow…earth is poison now. The Visitor ships leave, all except for the mothership. Diana’s vanity causes her to plan to use the nuclear device in the ship. John, on the other hand, is ready to give up, telling Diana she is welcome to be queen of the poison realm. But he does not get far, Diana shoots him dead. She then goes to take Elizabeth, but Mike, Julie an Martin bust in and try to fly the ship away from the earth. While they struggle Elizabeth starts walking to the control panel. Diana slips away, suddenly, Elizabeth grabs the two keys that started the process…she begins to sparkle, all Twilight like. She apparently has superpowers that neither the Visitors nor the human race possess. This really makes no sense,and no explanation is even made as to why she has super powers. It’s just accepted as a “logical” extent of being a hybrid. Kind of like how mules can fly or a wolpin can shoot lasers from it’s eyes. And she is apparently an Anikan Skywalker level tech genius, because she can pilot the mothership with zero training. She stops the mothership from overloading. She turns to everyone and speaks a word from the Visitor language which is revealed to mean Peace.
Mini series is over.