V: The Final Battle was a three-part miniseries that was broadcast on NBC on three consecutive nights from May 6 to May 8, 1984. It was the sequel to V: The Original Miniseries.
The first episode begins with a nightmare showing Mike Donovan and his son, Sean, trying to escape from a Visitor mothership with Visitor troopers in pursuit. Mike is knocked down by laser fire, Sean is shot in the back and apparently killed. Julie rouses Mike from his sleep as the Resistance prepares for a raid on a Visitor processing plant to rescue humans who have been repackaged into food cocoons. The raid is easily thwarted at the plant perimeter, due to the Visitors' advanced armor and security measures. In the raid's debriefing at the Resistance hideout, the team bickers over how things went wrong. Robin Maxwell's pregnancy is also at an advanced stage.
The rebels later get wind of a major event to be held at the Los Angeles Medical Center, where John is expected to announce a medical breakthrough - a universal cancer cure. Because of the extensive media coverage, the rebels infiltrate the hospital. However, while he can provide uniforms for the infiltration, Martin could not supply weapons because all Visitor armories were heavily guarded. The rebels scout the place and secure medical supplies while Robin seeks an abortion with Julie's help. They cancel the abortion because of potentially fatal complications to her.
Meanwhile, television reporter Kristine Walsh begins to doubt her association with the Visitors, because of Mike's request to find Sean aboard the mothership and a well-known doctor's stinging criticism of her at the hospital (and sudden turn-around due to Diana's conversion). During a scouting mission, the rebels succeed in capturing Willie, a friendly Visitor technician, and his human girlfriend Harmony, whom they bring to their hideout for study.
The hospital raid is a success, with Julie unmasking John's true nature. Martin and Lorraine, another member of the Fifth Column, prevent the mothership from cutting off the live feed. Diana also kills Kristine after she disobeys her orders to dispel the incident as a terrorist hoax and makes a desperate call for rebellion. After a firefight inside the hospital corridors, the rebels escape with help from the Fifth Column, who have assigned a transport crew to "capture" them; however, it is a Pyrrhic victory, as Julie (who got separated during the escape) is captured during her own escape from the hospital. The episode ends with Julie undergoing the conversion process.
Two mercenaries - Ham Tyler and associate Chris Farber - join the Resistance. Ham reveals the existence of an international resistance force that can supply armor-piercing ammunition plus other effective weapons for the war.
The fiasco of the previous evening forces Diana to have the scene re-enacted under heavy security, managing the audience at gunpoint, to be passed off as the actual broadcast. The Visitors storm the hideout, but the rebels escape with the help of Tyler and Farber and further advance warning from Ruby, who's now working at their security headquarters as a cleaner. They relocate to an old western movie studio.
Julie, now Diana's prisoner, is being converted. The chamber inflicts horrifying visions on Julie's mind, in an effort to brainwash her. As she resists the mental torture, Diana is forced to increase the intensity of the chamber. A pre-existing heart condition causes Julie to go into cardiac arrest, nearly killing her. Despite this, Julie is put back in the chamber. Frustrated with Julie's resistance to the process, Diana increases the intensity to maximum. It eventaully proves too much for her and Julie is finally converted. After the session, Mike Donovan bursts in and attempts to shoot Diana, but Jake kills him in time. The sight of this causes Julie's conversion to break. It is later revealed that the man appearing to be Mike is a Fifth Column agent in disguise.
Because of the danger of Fifth Column infiltration (especially now with the arrival of Diana's superior, Squadron Commander Pamela), Martin suggests that all major prisoners be transferred from the mothership to the security headquarters on the ground for further protection. Mark's girlfriend, Maggie Blodgett, who has seduced collaborator and Visitor Youth member Daniel Bernstein, brings this information to the rebels, who see the opportunity and rescue Julie. Daniel, however, kills Ruby after she cuts the power for the laser fencing, a critical part of the operation.
Once again in the ranks of the Resistance, Julie tells the others of a 30-day plan to steal all the water from southern California by means of a water pipeline to a Visitor mothership. With the aid of devices that shift their voices and make them similar to the Visitors, the rebels scout the facility and prepare to destroy it. Tyler questions Julie's loyalty, believing her to be converted, but she responds firmly and retains command in front of the others. However, her attempted conversion has left her scarred. She finds herself using her left hand, a side effect of the conversion process. She finally seeks comfort in Mike's arms. At the same time, Maggie confronts Mark over their relationship in light of her undercover liaison with Daniel. They make peace, and he proposes her to marry him; she agrees an they plan to do it as soon as possible.
The attack on the water facility goes as planned, and after placing explosives, a firefight ensues between the rebels and the aliens. Mark is wounded and sacrifices his life to cover the escape - something that Maggie would grieve over.
Later on, Diana and Stephen appear in a news bulletin along with Sean, whom Steven had Brian take out of stasis per a favor from Eleanor Dupres. It is a clear invitation for Mike to surrender to them in exchange for his son. Mike gives himself up and is taken on a mothership, while Ham and Julie bring Sean to safety. The rebels relocate to an old city jail afterwards, where their prisoner Willie gradually wins their trust when he helps Robin through her pre-labor stage.
A Fifth Column agent named Oliver visits Mike at his cell and offers a suicide pill to prevent him from divulging information about the Resistance and the Fifth Column, in light of Diana's ultra-potent truth serum. Jake kills Oliver and Diana injects Mike with the drug. The effects take place immediately, with Mike forced to compromise Martin, who is present. Martin tries to shoot Diana, but she escapes with the knowledge that Martin is a Fifth Columnist. Donovan and Martin hide in the mothership's airshafts.
The first few days after Robin's delivery prove to be challenging for her and the others. The male child dies while the baby girl, Elizabeth, begins to grow at a rapid rate. Julie and Robert's analysis of the male child's corpse reveals certain bacteria that only affected the boy despite his proximity to Elizabeth in the uterus. Encouraged by the sudden development, the duo decide to culture the germs as a potential weapon.
Mike Donovan and Martin escape by skydiving out of the mothership and Martin goes into hiding with other ground-based Fifth Columnists. After Mike reaches the jail, the team discuss testing the bacterium, now called the "Red Dust," but reject Ham's suggestion of using Willie as a guinea pig. Instead, the rebels capture Brian at the Bernstein house and frame Daniel. Steven retaliates by sending Daniel off to be processed as food.
The team locks up Brian, and Robin (with Elizabeth in tow) visits him in the middle of the night. However, the family reunion is short, as Robin seeks revenge by throwing a vial of the Red Dust into Brian's holding chamber, with fatal results. Father Andrew Doyle, the team's resident priest, carries Elizabeth off to safety while the others look at the outcome. While Ham and Mike mull over capturing a Visitor Youth member to be used as a human subject, Julie enters the chamber and proves the dust is non-lethal to humans.
Father Andrew brings Elizabeth to Diana, who makes them feel welcome, but later murders the priest after reading the Bible; the Bible makes Diana realize she is 'vulnerable.' The danger of compromise forces the rebels to evacuate and regroup at a coastal lighthouse complex, where more Red Dust stocks are produced. Ham and Mike also get into a small but physical argument over delivering the stocks to other resistance groups when a vaccine was not yet complete, one that would protect the Fifth Columnists.
Martin later asks Mike to stop producing the toxin, revealing the Visitors contingency plan: using their ships as doomsday devices if the situation was lost. Despite the team's debate over whether to attack or not, Elias Taylor successfully appeals to take a chance and possibly save the world.
The planning sessions take place, but Julie notices Sean overhearing the details. She then tells Mike of the possibility that Sean was converted before the exchange, which Ham later confirms. Sean escapes the hideout to warn the Visitors, but the original plan of using United States Air Force planes to spray the toxin into Earth's atmosphere was in fact a ruse and the rebels will use hot air balloons instead. Martin and a number of Fifth Column members arrive at the complex aboard a Visitor tanker vehicle, which will carry a stock of Red Dust for dispersal aboard the mothership. They are later administered with a vaccine for the Red Dust.
The raid begins in earnest and Sean's false information leads the bulk of the Visitor forces to secure all airbases for an attack that never arrives. The tanker strike team manages to steal aboard the mothership, where Mike closes all security feeds as the rest of the team pump the toxin into the ventilation system. Robert, Ham, and Chris lead the assault on the Visitor security headquarters. Red Dust mortar blasts eliminate the defenders with no human casualties. Desperate to escape, Steven kills Eleanor, but Ham takes him down long enough to douse his face with a bag of Red Dust. The balloons' mass dispersal of Red Dust around the world will allow the deadly bacteria to multiply in the Earth's ecosystem. The Visitor forces evacuate Earth.
Diana activates the doomsday device aboard the Los Angeles ship (after shooting John, who did not want any part of it) while Mike, Julie, Elias, and Lorraine are pinned down by Visitor troops in a ventilation tunnel. The Red Dust begins to circulate, killing more soldiers. Martin joins up with them as they face Diana at the bridge, where Lorraine attempts to disarm the auto-destruct machine. The other rebels and Visitors evacuate the ship while Martin brings it out of orbit. Elizabeth steps up and finally stops the countdown using her latent superhuman powers. Diana uses her conversion of Julie to distract her long enough to escape. Martin brings the mothership back to Earth.