Legion of Super-Heroes

Argo City on Krypton faces a disaster predicted by Jor-El. Alura Zor-El sends Kara to Earth with hopes she will reunite with Kal-El. A fragment from the exploding planet damages Kara's escape pod, placing her in suspended animation and delaying her arrival on Earth.

Kara wakes on Earth and takes the name Supergirl as she struggles with the planet's culture and her newly acquired powers. She fights Solomon Grundy, revealing her strength, and is rescued by Kal-El (Superman) and Batman. Kal-El suggests she travel to the 31st century to join the Legion Academy.

In the 21st century, Batman intercepts masked assailants raiding S.T.A.R. Labs, though they commit suicide before he can interrogate them. Kara's first clues about a larger threat begin to surface. Batman's intervention sets the stage for the mission to the future.

Kara travels to the future and is introduced to the Legion Academy by Mon-El. She immediately clashes with Brainiac 5, mistaking him for Brainiac, which strains their budding relationship. Over time, they overcome the misunderstanding and form a cautious alliance.

During a night search for their school pet Proty, Triplicate Girl spots Mon-Arl lurking near a restricted vault on the Academy grounds and is attacked, apparently killed. The incident triggers an investigation into Mon-El's loyalties. The Vault's danger hints at a deeper conspiracy.

The Legionnaires arrest Brainiac 5, discovering his involvement with the academy to penetrate the vault containing dangerous weapons. He explains he is countering an organization called the Dark Circle, though Kara believes him while others remain wary.

Recognizing the masked figures from the Academy's Dark Circle files, Kara frees Brainiac 5 from confinement. She learns that the Dark Circle seeks the Miracle Machine, a relic capable of bending reality.

Mon-El joins Kara and Brainiac 5 to infiltrate the vault and disable its security. They locate the Miracle Machine, but Mon-El reveals himself as a Dark Circle agent, stabbing Kara with kryptonite and summoning the Circle to overpower the Academy.

The Circle's leader is revealed to be Brainiac, who founded the Dark Circle in the 21st century to facilitate his resurrection. He plots to gain access to the Miracle Machine through Brainiac 5 and to rewrite reality to his advantage.

The Triplicate Girl, Invisible Kid, and Phantom Girl escape confinement and join Kara and Brainiac 5. The group liberates Dawnstar, Bouncing Boy, and Arm Fall Off Boy, preparing for a broader resistance against the Circle.

The team sends an SOS to the Legionnaires in space as Mon-El and the Circle engage their allies. Kara and Brainiac 5 race to stop the Miracle Machine, but succeed only by turning the predecessors against their creator, causing Brainiac to tear apart.

With the Miracle Machine spiraling out of control, Kara summons Alura's soul and resists the urge to reverse Krypton's destruction. She instead displaces the machine into another reality, averting the catastrophe.

The surviving students defeat Mon-El and the Dark Circle, and the returning Legionnaires grant Kara, Brainiac 5, and the other students full Legion membership, recognizing their bravery and teamwork.

In a post-credits scene, Kara informs Superman that she will stay in the 31st century and continues her relationship with Brainiac 5. Meanwhile, in Metropolis, Superman and Batman are struck by a beam blast, implying a new, ominous threat to Earth.