As Deathstroke continues to monitor Miss Martian aboard the Manta Sub, following at a distance just out of her telepathic range, he informs Black Manta that the Martian is progressing slowly. Aboard the sub, Miss Martian, the undercover Artemis disguised as Tigress, and Aqualad, telepathically talk to each other. All of Miss Martian's powers except her telepathy are still nullified by the inhibitor collar. Black Manta comes in and informs them that Miss Martian has 24 hours to finish curing his son or he'll kill her.
Nightwing teleports aboard Warworld and meets with Blue Beetle and the League. Blue Beetle tells Nightwing the made-up story that they had defeated Mongul but then the conqueror used a boom tube to escape with their comrades. Captain Atom puts the League on guard, watching the crystal chamber so that Mongul can't reactive the planetary weapons platform, and Blue Beetle begs Nightwing to let him help. Nightwing tells him that he needs to get some rest and Green Beetle and Blue Beetle teleport to El Paso. However, once they arrive, the two of them share a knowing glance and split up.
Sportsmaster and Cheshire secretly swim up to the Manta Sub and sneak onboard without Deathstroke noticing. Once they take out a guard, Cheshire reminds her father that she's only working with him so that she can kill Aqualad and avenge her sister. Sportsmaster doesn't care and plans to dispose of Black Manta to reestablish his reputation. Father and daughter sneak through the sub, disabling the security cameras and knocking out guards. Once they find a map, Cheshire enters the air vents and heads for Aqualad's quarters.
Miss Martian is willing to sacrifice herself for her teammates, but they refuse to let her die. They come up with a plan and Artemis calls to tell Deathstroke that she's taking a break. She leaves, sending a guard in, but Cheshire breaks in and knocks the man out. When she tries to kill Aqualad, still feigning a coma for the benefit of Deathstroke, Miss Martian stops her and telepathically tries to explain what they're doing. However, Deathstroke uses the inhibitor to shut down her telepathic powers as well, leaving her defenseless. He then contacts Black Manta and warns him that there are intruders aboard.
Artemis goes to the control center and sends the two guards to protect Aqualad. Once she's alone, she looks for the collar control unit. Meanwhile, Sportsmaster finds Black Manta and attacks him. Before he can kill the aquatic villain, Manta's men arrive and open fire. Sportsmaster disposes of them with an explosive chakram and returns to the attack.
As they fight, Cheshire wonders why Miss Martian is defending Aqualad, who she supposedly put into a coma in the first place. The guards open fire from the door and Cheshire knocks them back and seals the cabin door. Meanwhile, Deathstroke warns Artemis about Cheshire, telling her that Miss Martian is defending Aqualad since his health is the only reason they're keeping her alive. Artemis tells the mercenary that she's on her way.
Miss Martian fights without her powers and manages to disable the security camera. Once she's sure that Deathstroke isn't monitoring them, the Martian tries to tell Cheshire what's going on. Cheshire knocks her out and Aqualad, now safe from observation, tells Cheshire that Artemis is alive. Before he can explain further, Cheshire grabs him and prepares to cut his throat.
On Warworld, Nightwing scans the hangar bay and realizes that someone damaged the airlock controls. He also finds one of Robin's birdarangs and discovers that it is covered with scarab microbes, as if it had scratched Blue Beetle's armor.
Artemis disables Miss Martian's inhibitor collar and then heads for Aqualad's cabin. She finds Sportsmaster and Black Manta, still fighting, and Black Manta tell her to hold off Sportsmaster while he goes to rescue Aqualad. Artemis leaps to the attack and Sportsmaster prepares to unwittingly kill his own daughter.
When Black Manta gets to the cabin, he blasts his way in but Cheshire knocks him out and prepares to kill father and son. Miss Martian recovers, lets the collar phase through her body, and telepathically links Aqualad and Artemis with Artemis' family. They find themselves in a mental illusion of Artemis' and Cheshire's childhood bedroom. Artemis explains about her undercover mission and Cheshire accepts what she's saying. Sportsmaster figures that it's a Martian mind trick and Artemis tells her teammate to release them so she can prove what she's saying.
Back in the hallway, Artemis uses a move that her father taught her to take Sportsmaster down. He realizes that she's telling the truth and they're both fighting against The Light, and Artemis asks him for a favor. As the guards arrive, Sportsmaster and Artemis fake fighting to the death.
When Black Manta recovers consciousness, Miss Martian pins him and Cheshire to the wall. Cheshire plays along as Miss Martian tells her that she can go since they share a common enemy in Black Manta. Once the villainess slips out, Aqualad "attacks" Miss Martian, who retreats by phasing through the wall. Black Manta assumes that the danger to him brought his son out of his coma and embraces Aqualad.
Sportsmaster and Artemis "accidentally" knock out the guards as they fight, and then Sportsmaster slips away and goes to the control room. He blows it up, covering Artemis' sabotage, and then meets Cheshire in the docking bay. As they prepare to escape, Deathstroke and Cheshire arrive and attack them both. Sportsmaster warns his replacement that The Light will dispose of him just as they did Sportsmaster, but Deathstroke plans to take a seat on The Light's council. Artemis fights Cheshire and wonders why her sister came to avenge her when she doesn't like her, and Cheshire admits that she's mad that Artemis hasn't come to see her daughter Lian, Cheshire's niece.
Miss Martian arrives and attacks Deathstroke and Artemis, telekinetically pinning them to the wall so she can get her "revenge." As Sportsmaster and Cheshire swim clear, Deathstroke frees himself using concussion grenades. Miss Martin telepathically apologizes to Artemis as she telekinetically slams Deathstroke back into her teammate and then phases through the hull and swims away.
Later, Cheshire meets her mother Paula in Gotham City. Paula has been babysitting Lian and tells Cheshire to enjoy her time with her child because one never knows when they could die. Taking pity on her mother, Cheshire tells her that Artemis is alive.
Black Manta tells Vandal Savage and the Reach's Ambassador that his son is fully recovered. The Ambassador agrees that their plans have all come to fruition.
Later, Nightwing watches the news as the Ambassador announces that Blue Beetle single-handedly saved Earth from Warworld. When Blue Beetle comes on, thanks The Reach for giving him the scarab, and exults in his power, Nightwing puts it all together and realizes that Blue Beetle has betrayed them.