War of the Satellites

The UN learns that ten Sigma satellites were destroyed by a mysterious space barrier. A small missile-like capsule lands on Earth and is handed to authorities. During the briefing, the capsule's message proclaims to be from the Masters of the Spiral Nebula Ghana, aliens who declare Earth a disease and announce a quarantine to protect the universe.

The capsule's origins remain unknown, defying analysis. The UN council reads aloud the alien message, revealing the warning and the quarantine. The moment establishes the extraterrestrial threat and sets the stakes for Sigma.

Dr. Van Ponder, head of Sigma, is knocked off the road by a ball of light while driving to a UN meeting. The incident kills him and hints at nonhuman interference. This event marks the first direct sign that aliens are involved with Sigma.

Unbeknownst to officials, aliens have assumed Van Ponder's form and infiltrate Sigma. Van Ponder later splits into two replicas to broaden their control and impede the project.

A series of natural disasters erupts worldwide, and speculation grows that these events are part of the aliens' warning. The disasters escalate the sense of impending danger beyond Sigma.

Astronomer David Boyer notices that Van Ponder bears identical markings on both arms, a clue that there may be more than one version of the scientist. This detail raises suspicion about who is real and who is an imitation.

In a lab scene, Van Ponder doesn't notice his hand being burned by a torch. John Campo rushes for Doctor Howard Lazar, and Van Ponder later appears to heal the wound, leaving the hand intact. The episode underscores the alien's extraordinary abilities.

David investigates Van Ponder's demolished car and concludes that no one could have survived the crash. He learns the Sigma launch is moved forward to occur within hours, and, just before blast-off, he sees Van Ponder replicate himself. The timing tightens the tension around the mission.

Following the successful launch, Van Ponder paralyzes John and reveals that he is an alien. He offers to transform John if he aids him, but John refuses and is killed. The crew begins to realize the true nature of the threat.

Sybil Carrington enters the control room and learns of John's death. Howard Lazar asserts John was healthy, while David accuses Van Ponder of murder. Van Ponder murders Howard, and David is arrested on the accusation.

Sybil searches for Howard, spots Van Ponder, and takes refuge in the solar radiation room. Van Ponder replicates himself in front of her; one replica pursues David, while the other attempts to seduce Sybil. The duplications intensify the danger around the crew.

As the satellite nears the space barrier, Van Ponder orders the pilots toward it. David confronts a replica, wounds it, and ultimately kills Van Ponder, while the Sybil-bound replica also dies. The confrontation decides the fate of Sigma's mission.

David detonates a radiation blast from the satellite, catapulting them through the barrier. He rescues Sybil from the radiation room just before the blast, and the plan succeeds as Sigma passes through Andromeda at light speed. The crew escapes the alien threat and completes their risky mission.