Commentator G. Gordon Godfrey takes to the airwaves to complain about the launch of an Earth-Mars comsat at Cape Canaveral. He points out to his viewers that they’re trying to contact aliens in the middle of an alien invasion. In Palo Alto, Wally West is watching the TV when Artemis comes in and says that she’s ready. He reminds her that he’s not happy with her decision and blames Nightwing for asking her to help, but Artemis says that they need her help and nothing could go wrong.
Thirteen Hours Later
Nightwing tries to revive Artemis without success and is finally forced to admit that she’s dead.
At Mount Justice, Nightwing reviews the status of Roy Harper and Impulse, who are both being monitored. They’ve had no luck identifying the Light’s new partner. Miss Martian and Lagoon Boy arrive and flirt, much to Superboy’s disgust. He starts to leave until the briefing as Artemis arrives, and Nightwing says that it’s time for the briefing. Nightwing informs them that they are on a covert op to protect the satellite to stop anyone who hates aliens from sabotaging the launch. He plans to go with them, saying that he’s eager for action.
The team arrives at Cape Canaveral where Carol Ferris and Martian Manhunter is addressing the press. Godfrey asks why they should want to contact aliens and Carol points out that Earth and Mars are next-door neighbors. Martian Manhunter points out that they need allies and leaves to join Superman, much to Godfrey’s disgust. In the sky, “Martian Manhunter” reveals that she’s Miss Martian in disguise, and using her powers to levitate Superboy, disguised as Superman. She points out that they have to maintain the illusion that the League members standing trial on an alien planet are still on Earth, but Superboy still isn’t happy.
Nightwing and Artemis maintain a watch from an observation gantry while Lagoon Boy is in the nearby ocean. He’s less than happy that Miss Martian is in the skies with her ex-boyfriend. Meanwhile, nearby in the waters, a manta-sub drops off a missile launcher and Black Manta’s manta-men prepare to open fire on the satellite.
With 52 minutes until launch, Nightwing thanks Artemis for coming back. She admits that it’s nice to be back and that she’s been missing the action. Artemis also knows that Wally is worried because she might want to come back to Young Justice full time, and admits that she likes the rush.
In the bioship, Superboy remains silent until Miss Martian points out that the breakup was his idea. He reminds her that she abused her telepathic powers, violating their enemies’ minds and leaving them in a catatonic state. Miss Martian asks why he hasn’t told Nightwing, and Superboy admits that he had hoped she cared enough about him to stop. Instead she tampered with his mind to make him forget how upset he was. Miss Martian apologizes but he wonders if she’s sorry she did it or sorry she got caught.
Before they can pursue the matter further, Lagoon Boy reports in that he’s spotted the missile launcher. Nightwing tells him to stay put and Superboy says that he’ll move in to help the “rookie.” Offended, Lagoon Boy attacks immediately, enlarging to giant size, and the manta-men attack him and launch a land assault. Nightwing and Artemis take them on and Nightwing tells Superboy to pilot the bioship while Miss Martian goes to help Lagoon Boy. She grows gills and fins and enters the water while Superboy fires on the land forces.
Aqualad arrives to shock Lagoon Boy unconscious and then tells his men to launch. Superboy fires to release the locking clamps on the rocket while Carol tells her technicians to begin the launch. Using the bioship, Superboy fends off an incoming missile while Artemis gets an idea. Realizing that the manta-men’s helmets enhance light for underwater vision, Artemis fires a flare-arrow, temporarily blinding them.
The manta-men in the water bring Lagoon Boy to Aqualad, who says that their partner will want him as a specimen. He has them take Lagoon Boy to the flyer and tells his men to launch all of the missiles while he takes command of the ground assault.
Superboy continues to shoot down the missiles while Nightwing and Artemis take on the ground forces directly. Aqualad emerges from the water to face them.
In the ocean, Miss Martian sees the unconscious Lagoon Boy and prepares to go after him, but Superboy reminds her that the rocket is the priority and he can’t fend off all of the missiles. Miss Martian attacks the underwater forces but they manage to launch a missile. Using her telekinetic abilities, she pulls it back around and uses it to destroy the missile launch. Before passing out from the concussion, Miss Martian sees them taking Lagoon Boy away.
Artemis tries to get through to Aqualad, who says that he wants to destroy them. He telekinetically creates a water creature to attack them. Meanwhile, Carol and her men launch the rocket, but Aqualad fires a mini-missile from his armored suit. Artemis intercepts it with a rocket-arrow but Aqualad stabs her with a water sword. While Nightwing goes to his teammate’s side, Aqualad orders his men to retreat. However, he watches in surprise as the rocket blows up.
Superboy and Miss Martian arrive as Nightwing tries to revive Artemis without success. He finally admits that she’s dead.
Later, Aqualad reunites with his father, Black Manta, who congratulates him on his success. He tells his father that the rocket must have malfunctioned and their victory was luck, but Black Manta says that he smuggled a bomb onto the rocket days ago. He wanted to see if Aqualad would take credit for a success he hadn’t accomplished, and would have arranged another test if his son had succeeded. However, Black Manta is proud of his son and tells him that he’s ready for the next level.
At Mount Justice, the team gathers to mourn Artemis. Superboy considers approaching Miss Martian but thinks better of it, and tells Mal that they’ll find Aqualad and Lagoon Boy. Mal wonders where Nightwing is and Superboy tells him that he went to tell Wally.
In Bludhaven, Nightwing goes to a warehouse and meets with... Aqualad. Wally and Artemis are there as well and Aqualad reveals that he faked stabbing Artemis as part of their ruse to convince Black Manta that Aqualad was on his side. Only the four of them know that Aqualad is working undercover. Aqualad tells them that he’s proven his loyalty to his biological father, who is moving him closer to the Light and its new partner. He admits that he had to let them destroy the rocket to maintain his cover, and promises that he’ll find a way to rescue Lagoon Boy.
Nightwing then gives Artemis a magical charm created by Zatanna that will disguise her appearance. When she wonders how he got something so specific from Zatanna without blowing Artemis’ cover, Nightwing explains that she has a history with the sorceress. Wally and Artemis kiss before separating. Artemis goes with Aqualad while Nightwing tries to reassure Wally. However, he’s well aware that it will get more dangerous from here.