Synopsis: The clash begins with an image of a sprawled Elongated Man lying on the pavement in defeat. Nearby Metamorpho is engaged in a battle with the supervillain Parasite. Grabbing Parasite by the arm, Metamorpho swings the Parasite right upside a bus. Barely fazed, Parasite uses the power he absorbed from Elongated Man to overwhelm Metamorpho. Stealing Metamorpho?s powers, Parasite turns to notice the dark knight waiting for him. Batman, however, is no match for the super powered criminal and contacts the Watchtower for assistance.
Elsewhere, a plane flies out of control straight into city. Before the situation gets too bad, however, Superman blows out the fire on the wing and carries the plane to safety. J?onn radio contacts him, asking for his aid. Before Superman can even respond a red and yellow blur flies past him, blowing Superman?s cape straight over his head! Landing the plane to safety, Superman rushes to help defeat Parasite. By the time he finally gets there, Superman discovers what the blur was; the powerful superhero Captain Marvel! With a bit of dismay on his face, Superman shakes Marvel?s hand upon learning that the new leaguer is his biggest fan.
As the five superheroes begin to leave the scene where they fought Parasite, journalists and reporters, including Lois Lane, begin to swarm Captain Marvel. Marvel answers a few questions to Lois. He tells the media that he is amazed to be a part of the League, and that he is happy that Lex Luthor is being given a second chance. He also admits to being a Faucet City boy at heart. Before more questions can be asked, the hero of the day takes off and lands near a public school. Yelling ?Shazam? he turns into a little kid and sneaks into a classroom. His alter-ego, Billy Batson, is late for class?
Later, presumable after school, Captain Marvel is hanging out at the Justice League Watchtower. Friendly to everyone he meets, he says hello to several members before high-fiving Captain Atom. Walking into a room now, Marvel stops to peer into a chess game being played by Vigilante and Shining Knight. Before he can get too relaxed, however, a noticeably irritated Superman calls him into a private meeting.
Surrounded by the founding seven members of the Justice League, Marvel is berated for his earlier comments to the media by Superman. The newspaper took his words as an endorsement for Lex Luthor as president. Although Marvel is still convinced Lex Luthor has changed for the better, Superman is still suspicious of his former foe?s political run. Telling Marvel not to make anymore public statements without the League?s approval, Superman sends him away.
Meanwhile, Lex Luthor appears on a TV show called the ?O?Bannon Agenda? answering questions about his political run. Changing the subject, Lex decides to use his air time to discuss his newest project, Lexor City , a city built for people looking for a second chance. Luthor invites Superman on TV to the opening ceremonies for his new city, as Superman continues to become more and more suspicious.
Down on Earth, the World?s Finest take on a hoard of criminals. Even while concentrating more on their problems with Lex and Captain Marvel then with the fight at hand, Superman and Batman easily dismantle their opponents. Batman tells Superman that the entire league likes Marvel. All of a sudden Emil Hamilton patches his way through Superman?s communicator. He has a problem.
At the lab, Emil Hamilton shows Superman his problem. Four pounds of weapons-grade kryptonite have been stolen. Although Batman states Luthor?s technology was used to break in, he is not convinced Luthor did the crime. Batman recommends Superman that goes to the charitable event Lex invited him to, and investigates the matter first hand.
At the opening ceremony, Lex is truly charismatic. Stating his plan to house thousands who live in poverty, Lex finishes his speech with a toast to Superman. Mercy comes over to speak to Lex, a conversation Superman overhears. When he hears Lex talking about an escape route, Superman beings using his X-ray vision to find a weapon. Underneath the children?s playground, the man of steel finds a ticking weapon and begins to clear the area. Meanwhile, Billy Batson, who had been at the event in his child form, transforms into Captain Marvel.
While in the process of dismantling the playground, Superman is stopped by Lex Luthor and Captain Marvel. Lex states the ?bomb? is an experimental generator, powered by kryptonite. Logically, Marvel suggests the trio call the Atom, and have him check Lex?s story. Unfortunately, Superman is in no mood for waiting. And he isn?t going to be stopped by Captain Marvel either?
Throwing Marvel aside, Superman continues to destroy the playground. Marvel quickly gets up and throws Superman into a building in retaliation. Both heroes reset and charge towards each other. When the collision finally happens, the resulting aftershock rocks Lexor City, destroying countless windows. Marvel takes the brunt of the hit, but quickly rebounds by tossing a bus into Superman. This move results in yet another building being destroyed. Now in the air, the two mighty heroes trade furious hit after furious hit, demolishing Lexor City in the process. Using a bank safe door he rips out, Superman slams the door onto Marvel repeatedly, until Marvil is apparently down for the count. Superman then drills a hole through the playground and enters the room where the ?bomb? is. Captain Marvel has also found his way down there, after taking a few punches Marvel grabs Superman and holds him in the air. Yelling his trademark ?Shazam? he calls for lightning bolts to strike down on Superman. On his third call, however, Superman uses his strength to switch his place with Marvel?s and Marvel takes the lightning bolt to the chest. This causes him to revert to Billy Batson. Unable to say the words needed to become Captain Marvel again, Billy can only watch as Superman uses heat vision to destroy Lex?s device.
Back on the surface, the Atom and Batman have arrived at the scene. Apparently Lex was telling the truth, the device was not a bomb or a weapon. Refusing Superman?s offer to pay for the damage, Lex sadly states that this problem is on him and leaves, taking a trail of reporters with him.
Again the private meeting room, Captain Marvel reverses the roles?now berating Superman and the League himself. Stating that the League no longer acts heroic, the Captain leaves the Justice League permanently. After he leaves, Batman tells Superman that he was set up by multiple people?
In a private room Lex Luthor celebrates his success. Superman not only destroyed his generator as he had hoped, but also most of his city as well. Pouring two glasses of wine, Lex raises his glass to his mysterious counterpart. As the camera turned, Lex?s company is revealed as Amanda Waller, head of Cadmus?
