Elseworld's Finest: Supergirl & Batgirl

Elseworld's Finest: Supergirl & Batgirl (1998) is an Elseworlds comic book by Tom Simmons, Matt Haley and Barbara Kesel.

It is based in a world in which Bruce Wayne was never Batman, and the infant Kal-El did not survive long enough to become Superman. The orphaned Barbara Gordon becomes Gotham's near-dictatorial protector, and Kara Zor-El as the Girl of Steel teams with Lex Luthor and the Justice Society.

Main characters

 * Supergirl (Kara Zor-El): After Krypton's explosion, she is the only survivor of Argo City. She lands on Earth already knowing the exploits of the Justice Society of America and joins them. Lex Luthor becomes her mentor and friend.
 * Batgirl (Barbara Gordon): When Bruce Wayne's family is targeted by Joe Chill, Commissioner Jim Gordon interferes, which leaves both him and his wife dead. Barbara takes her father's gun and arrests the murderer. Barbara now wears the cape and cowl of Batgirl and rules Gotham with tyrannical furor, using both might and technology, having created the Oracle Supercomputer to aid her.
 * The Joker: The Joker is obsessed with Batgirl and desperately tries to win both her attention and love. Has the strength, physique, and costume of a circus strongman.
 * Bruce Wayne: Billionaire philanthropist, he is the equivalent of Alfred to Barbara, helping her fund her hi-tech gadgets and helping her hide her secret identity.
 * Lex Luthor: Primary benefactor of the Justice Society, he revolutionized life in Metropolis after developing a state-of-the-art solar battery and looks to open a new battery-making factory in Gotham. He oversaw the design and construction the JSA headquarters.
 * Professor Emil Hamilton: Discredited and humiliated, Hamilton seeks revenge against Lex.

Secondary characters and cameos

 * The Justice Society of America
 * Wonder Woman (Diana Prince): With both Batman and Superman absent in this continuity, Diana is the leader of the Justice Society. She is Supergirl's adoptive mother.
 * Tarantula: This hero is male, which implies that his secret identity might be John Law. He wears Catalina Flores' costume.
 * Captain Marvel: This Captain Marvel is African-American (although a flashback shows the traditional Captain Marvel). It's possible this is John Henry Irons having taken over the Marvel mantle, as his costume combines elements of the standard Marvel costume and his Steel armor.
 * Big Barda
 * The Flash: Flash wears armor and his mask completely covers his face, with yellow "horns" that extend from his chin and wrap around his temples.
 * Revenant: A glowing magenta male hero who resembles Johnny Thunder's Thunderbolt.
 * Hawkwoman replaces Hawkman. This version is a Thanagarian.
 * Green Lantern: Abin Sur never died in the crash and is now a member of the JSA.
 * Doctor Midnite: This version of Doctor Mid-Nite (note the different spelling) is a woman with a purple and black costume.
 * Vectron: a hero that resembles Apokolips' Metron.
 * Ambush Bug: His costume resembles armor instead of skin-tight spandex.
 * Interceptor: A female super-hero that can fly.
 * Robin (Tim Drake): Makes an appearance as a watchman for the Justice Society.
 * Black Canary: Makes an appearance inside JSA headquarters. This incarnation is a black woman.
 * Jade: Makes an appearance inside JSA headquarters. She does not appear to be different from the normal continuity aside from slight design changes in her costume and skin tone. However, it is implied that she and Abin Sur share some sort of father-daughter relationship.
 * Star Bolt: A hero also seen in JSA headquarters. His name may be an allusion to Starman. Alternatively, skin and eye coloration leads one to suggest that he may be Starfire's brother, Tamaran's Prince Ryand'r (called Darkfire in main continuity). Starfire herself is glimpsed in cameo, but never named.
 * Firestorm: Seen inside the headquarters, trying to impress Jade.
 * Asteria: A heroine wearing a red jumpsuit decorated with orange and blue stripes on her shoulders.
 * The Captain Marvel and Black Canary of the normal DC Universe are seen in a flashback.
 * Two-Face: Mentioned. He is the main villain of Barbara Gordon's The Binary Beast, a book based on his crimes and Batgirl's capture of him.
 * A novel named Killer Moth hints at another one of Batgirl's foes (Killer Moth).
 * The President of the United States appears to be Elvis Presley.

Plot summary
Barbara Gordon is Batgirl, a crime-fighter who rules Gotham City with an iron fist. Wonder Woman and the rest of the Justice Society have been permitted to make a public announcement inside Gotham Arena, where they introduce Supergirl and Lex Luthor to the Gothamites for the first time. Lex announces his plans to construct a factory in Gotham, employing a large number of its citizens. Ambush Bug senses a disturbance and teleports to find Luthor's driver being attacked via gas by an unknown assailant. Oracle stops him before he can investigate. As Lex leaves the arena, he is kidnapped by the Joker and Professor Hamilton.

As the news of the kidnapping reaches the JSA, Batgirl sets it upon herself to save Luthor single-handedly. Supergirl is told by Wonder Woman that Batgirl will not allow any Metahumans to enter Gotham, but Supergirl becomes infuriated and rushes to Gotham anyway. Batgirl sees Supergirl as a threat to her mission. She confronts her but Supergirl avoids a lengthy battle by reasoning with Batgirl. Meanwhile, Professor Hamilton reveals that he is holding Luthor captive so that he can expose to the world how he and Lex discovered the solar battery. He claims that Lex ruined his life and reputation when he tried to reveal the truth to the world. The Joker has been using a mineral-based steroid-like serum (possibly a variant of the Venom steroid used by Bane in regular continuity) to enhance his strength so that he can win Batgirl's attention. Luthor offers the Joker employment with the additional incentive of more of the minerals on which Hamilton based his steroid serum.

Batgirl and Supergirl start tracking Professor Hamilton and the Joker. Barbara leads Supergirl to an underground room, which is lead-lined and protected with a Kryptonite doorway. Batgirl leads Kara to a room and they discover the body of baby Kal-El, preserved in a test tube. This is the actual basis of Lex's "solar battery" invention, and the discovery makes Supergirl furious. Lex claims that he feared Kal-El would become dangerous, and that is why he killed him and befriended Supergirl when she arrived on Earth. Ready to meet her fury with Joker's strength, Luthor awaits while Batgirl and Supergirl rush towards him. Supergirl battles the Joker, but is unable to match his strength because the steroid serum he has been taking is infused with Kryptonite. However, Batgirl rescues her. Kara is about to kill Lex, but Batgirl stops her. Lex was the man who hired Joe Chill to murder Bruce's parents, which means he is also responsible for the death of Barbara's parents and must be brought to justice. Luthor, Hamilton and the Joker are arrested, and a friendship between Batgirl and Supergirl starts to grow, even to the point of an out-of-uniform Kara coming to Barbara's latest book signing.