The year is 2201, one year after the Star Force returned to Earth bringing the Cosmo DNA device which rid it of the radioactive pollution caused by Gamilon's planet bombs. Since that time, no longer threatened by outside forces, Earth has recovered and expanded its naval power and terrirory to the periphery of the Solar System. Most of the Star Force crew are assigned to various posts on Earth, although the Argo is currently on assignment as the flagship of the Solar System's peripheral defence patrol fleet. Commanding it is Deputy Captain Derek Wildstar. Unknown to Earth, a new threat lurks in outer space. In the palace of the Comet Empire -- a huge mobile city fortress shrouded in a plasma field which makes it resemble a white comet -- its green-skinned ruler, Prince Zordar, plans for his next conquest, Earth. His minions, daughter Princess Invidia, and Generals Dire and Gorse, gather to review the plans for the Earth, the defenses of which are deemed vastly inferior. An easy victory is predicted. But suddenly, a surprising voice pierces the air. Gamilon Leader Desslok steps out of the shadows of the throne room to chide the court for its overconfidence. They have failed to consider the Star Force. Invidia, immediately showing her disdain for the former Gamilon ruler, scoffs at this, asking whether this is the same Star Force which single-handedly wrecked Gamilon. Desslok scoffs at her arrogance, and insists that unless the Star Force is dealt with, the Comet Empire will be unsuccessful. He convinces Emperor Zordar to allow him to personally take care of the Star Force. Meanwhile, Comet Empire strike planes begin stealth attacks on Earth's defence patrol fleet. Wildstar takes his Superstar flighter out on a solo mission to chase the mysterious enemy, only to be called back to the ship which has been crippled by an enormous EMF surge which has passed through the Solar System. The surge burns up many of the Argo's electrical circuits, but the communication system holds out long enough to record a garbled radio message from an unknown source. Could it be related to this new enemy, they wonder. As the damaged Argo returns to Earth, it crosses flight paths with Earth's new flagship, Andromeda, commanded by Captain Gideon, on its maiden flight. Each captain masks pride with principle, and refuses to yield airspace. The two ships come within mere meters of collision. The Argo descends to Earth.

As the Star Force reunites to honor Captain Avatar's memory, Derek Wildstar says that he scouted what he thinks is a new and potentially very powerful and dangerous enemy. He then goes to the Andromeda and confronts Captain Gideon, who turns out to be one of his former instructors, about the near-miss in space. Gideon says that even though the Argo had landing priority as a returning spaceship, it still would have had to yield to the Andromeda because the latter was Earth's highest-ranking starship. Despite Wildstar's protests, Gideon simply tells him he will "learn the hard way." Wildstar leaves Gideon's quarters along with former crewmate Sandor, who gives him a tour of the Andromeda, saying how computerized the ship is. When Wildstar asks about the radio message, Sandor plays it back; although mostly garbled, it appears to contain a woman's voice. Wildstar asks about the improvements to the Argo, and Sandor mentions that the Earth Defense Force wants the Argo just as computerized as the Andromeda. The news upsets Wildstar, who confronts the Earth Defense Council's commander, just as a massive blackout occurs. On board the Comet Empire, which was responsible for the blackout, Desslok tells Zordar that the Star Force will head to Telezart once they decipher Trelaina's message. Zordar puts Desslok in charge of handling Trelaina and the Star Force.

Sandor and Wildstar try to decode the message Wildstar received, but the best either of them can determine is that it appears to be a jammed distress call vaguely warning the Earth of some sort of danger. Believing the message and the blackout may be related, Wildstar unsuccessfully tries to get the Earth Defense Force to listen. He then decides to take the Argo -- unauthorized -- out into space, even though he isn't fully sure there is a threat to Earth. Wildstar sends a message to the old Star Force crew, emphasizing that their participation in this mission is strictly voluntary since the mission isn't authorized. Sandor agrees to go, but Venture wants time to think it over. Nova is torn between letting Wildstar go and asking him to stay. Desslok meets with his former battle staff and has the Gamilon fleet go to Telezart to wait for the Star Force. Wildstar boards the Argo and is surprised when it powers up, then discovers Sandor and Orion on board. The rest of the old bridge crew, minus Venture and Nova, also join Wildstar on the Argo as it prepares to depart Earth.

The Earth Defense Force learns that the Star Force's personnel have abandoned their posts and are boarding the Argo. It sends a message to the Argo ordering those on board to leave the ship and return to their posts immediately. Derek Wildstar acknowledges the message, but says the Star Force is made up of volunteers, so the crew might not obey. Meanwhile, Mark Venture meets with Dr. Sane and Nova at Captain Avatar's memorial and discusses his concerns about whether or not to go. Sane replies that the Star Force itself is special -- the crew is willing to take risks even if it isn't sure of the outcome. The EDF's commander contacts the Argo one last time asking the Star Force to abandon its mission or risk being branded as mutineers, but Wildstar says they are taking off anyway. As the Argo begins to move, Venture appears on the bridge and handles the ship's departure. Meanwhile, the EDF, on its commander's orders, launches unarmed magnet missiles, two of which attach to the Argo. The ship starts its Wave Motion Engine and breaks free of the missiles. Using one of its battle satellites, the EDF tries to stop the Star Force, but the Argo destroys the satellite. The EDF's commander allows the Argo to enter space, secretly wishing its crew luck even though they are now considered rebels.

As the Argo continues its journey to space, the trip is uneventful until the ship encounters three fighters from the moon's base station. Wildstar orders the bridge crew to their combat stations, then realizes that the fighter group is the Black Tiger squadron, led by his old crewmate Conroy. The Black Tigers have abandoned the moon base to join the Argo. Wildstar then discovers Nova on the ship. He admits he wanted her to stay on Earth for her own safety. Nova replies that she's a Star Force member too, and she wanted to go on the mission regardless of the danger. In the distance, Conroy sees the Andromeda and alerts Wildstar. Realizing the Argo is no match for the Andromeda, Wildstar heads for an asteroid belt near Jupiter. The Argo loses the Andromeda in the belt, but Gideon maneuvers his ship around the belt and meets the Argo on the other side. Gideon orders Wildstar to return, but he refuses. The Argo and the Andromeda approach each other on a collision course, but when Gideon sees the Star Force's determination to continue its mission, he holds his fire. Similar to their first encounter, the two ships narrowly pass each other, and the Andromeda lets the Argo continue. Gideon sends a message to the Argo complimenting Wildstar and the rest of the Star Force on their courage and dedication.

The Argo answers a distress call from Space Marines on planet Brumas.

The Space Marines cause a flurry of problems for the Argo's crew, including disrepecting Nova's authority and literally creating a mess in the mess hall. Two sub-space submarines from the Comet Empire then attack the Argo. The Star Force destroys the submarines, but they still don't know what kind of enemy they are facing. Sandor has the ship land on a planet so the damage can be repaired. Meanwhile, the Argo's crew and the Space Marines get into a brawl and Wildstar and Sergeant Knox, the Space Marines' leader, get into a fist fight, which Dr. Sane breaks up. Dr. Sane says that Knox has to adjust to not only having been defeated at Brumas, but also to having had to relinquish command to Wildstar. On the Argo's bridge, the crew receive a garbled message from Telezart, but they are able to at least extract navigational coordinates from the message. The Star Force sets course for Telezart.

As the Star Force reaches the coordinates from Trelaina's last message, it receives a new message. The Argo warps to the new coordinates, but finds itself in the middle of a space cyclone. When the ship reaches the middle of the space cyclone, however, the Star Force finds the remnants of several ships that never made it out. The Space Marines grow restless. Dr. Sane prescribes the holography room as treatment for them. Meanwhile, the crew discovers that the center of the cyclone accelerates time, aging everyone's uniforms -- and the ship -- to where they are disintegrating. To make matters worse, a Comet Empire fleet has launched an attack on the Argo. Trelaina then radios new coordinates to the Argo, allowing it to exit the cyclone -- and the time trap -- and counterattack.

Wildstar makes contact with the Earth Defense Force but reports he hasn't been able to find out more about the Comet Empire. The EDF says that so far, nobody on Earth knows that the Comet Empire is more than just a comet. The Star Force then sees a Comet Empire ship, and Wildstar orders that the pilot be taken prisoner. When Dr. Sane runs some tests on the captured pilot, he discovers that the data are nearly identical to one of the Argo's crew members. The Star Force tries to interrogate the pilot, but he refuses to talk. The pilot then escapes, but Wildstar orders the crew to let him go, then tracks the pilot to the Comet Empire's fleet. The Comet Empire refuses to allow the pilot to return. Wildstar radios the pilot, offering him asylum. Unsure of what to do, the pilot identifies himself as "Mazor" but crashes his plane into the side of the Argo, leaving the crew wondering if he had intended to land or attack. Wildstar then orders the Argo into the midst of the Comet Empire's fleet, and the ships destroy each other attempting to fire on the Argo.

As the Argo continues to Telezart, it receives another message from Trelaina warning them of a meteor swarm. The crew verifies the swarm, which proves that Trelaina intends to help them. Back on Earth, the large comet is expected to arrive in one hundred days, prompting Captain Gideon to request five more ships similar to the Andromeda. Earth's population also begins to get suspicious when all non-defense space flights are grounded. The Argo encounters the meteor swarm, discovering that the meteors are absorbing the ship's speed and slowing it down. It then encounters enemy fire and uses the meteors to create a defensive shield around the ship. However, the meteors form a whirlpool that drains the Argo's energy. Believing the ship defenseless, the Comet Empire fleet attacks again, but -- thanks to Sandor -- the Argo is able to use its Wave Motion Gun to defeat the fleet. The Star Force then receives a message from an old enemy -- Gamilon Leader Desslok.

Desslok of Gamilon sets his plan into action against the Star Force.

After his initial plan to defeat the Star Force fails, Desslok of Gamilon implements one more trap...

The Star Force arrives at Telezart and look for Trelaina.

The Star Force defeats the last of the Comet Empire's resistance at Telezart and finally meets with the mysterious Trelaina.

The Star Force learns of the true nature and threat of the White Comet, Trelaina's dark past, and are ordered to return home to help fight the oncoming threat. But Venture may have other ideas...

The Argo prepares to leave Telezart, but will Venture choose to stay with Trelaina on her doomed planet?

Wildstar orders a warp to take the Argo to the Comet Empire. When the Argo reaches the coordinates, however, the Star Force discovers that the Comet Empire is headed to Earth, while they find themselves quickly surrounded by Gamilons, led by Desslok. Wildstar tries to convince Desslok not to attack, but Desslok sends his entire fleet after the Argo, heavily damaging the Argo's landing dock and surrounding the ship. Wildstar points the Argo at Desslok's ship, intending to use the Wave Motion Gun against it. Just as the gun reaches full charge, however, Desslok transports several space mines directly in front of it, preventing the Star Force from using the gun. Wildstar then has the Argo do a small space warp, causing his ship to ram Desslok's. He then leads a boarding party onto Desslok's ship. Meanwhile, Nova is nearly hit by gunfire outside the Argo. Venture rescues Nova but is knocked off the ship and into space, presumably dead. The episode ends with Wildstar, having been injured by falling debris, holding Desslok and his aide at gunpoint.

Although badly wounded and bleeding, Wildstar confronts Desslok on his ship. Desslok prepares for a duel, but Wildstar collapses from the loss of blood before he can fire. Having followed Wildstar, Nova rushes to his side, confessing her love for him and for the Earth. Realizing that Nova and Wildstar love Earth as much as he loves Gamilon, Desslok lowers his weapon, giving them a piece of advice as he leaves: the Star Force attacked Gamilon at its weakest point, from underneath. He suggests they attack the Comet Empire the same way. Wildstar learns of Venture's fate and briefly mourns the loss, then finds out about the Earth's decision. Since the Comet Empire is in the water, Wildstar decides to submerge and attack it from below, using the suggestion from both Desslok and Gideon. However, the Argo only has torpedoes, as the attack on Desslok's ship rendered the main guns and the Wave Motion Gun unusable. Meanwhile, in space, Trelaina recovers Venture's body and discovers he is unconscious, but just barely alive. A surrender party launches from Earth to meet the Comet Empire. Wildstar sends a message to the surrender party advising them of the Argo's attack and to clear the area around the Empire.

As the Argo launches torpedoes against the Comet Empire, Zordar orders the Empire to be launched. The Argo pursues the Empire, positioning itself out of range of its guns, and maneuvers itself below the Empire. Sandor discovers the Empire's weak spot: an opening in the base from where the Empire's planes are being launched. Wildstar leads an attack team through the opening, but Sandor is hit and unable to walk. Knox, the leader of the Space Marines, says he'll finish the mission himself as a way of thanking the Star Force for rescuing them. He attaches bombs to the Empire's energy source, then detonates them, rendering the Empire unable to move. Meanwhile, Zordar escapes with Invidia, Dire and Gorse in a new space fortress.

Zordar's space fortress launches an assault on the Argo, heavily damaging it and injuring several of its crew. As the Star Force watches helplessly, Zordar attacks the Earth. Meanwhile, Trelaina uses her life force to bring Mark Venture back to life. Derek Wildstar orders the crew evacuated from the Argo. He boards the last remaining evacuation ship, but activates its autopilot and jumps off at the last minute. On board the Argo, he prepares it for its final trip -- a collision course with Zordar's ship. Suddenly, he sees Nova, who decided to remain to help him. As Wildstar and Nova steer the Argo toward Zordar's ship, they receive a communication from Trelaina, who is holding an unconscious -- but alive -- Venture. Trelaina returns Venture to the Argo, then says that Wildstar doesn't need to sacrifice the ship; she will fight Zordar. When Trelaina appears, Zordar stops his attack and tries to retreat, but Trelaina destroys his ship, sacrificing herself in the process. Wildstar and Nova salute Trelaina, and the Argo returns to Earth.