For the Rebirth series from 2016, see Superwoman: Who Killed Superwoman?.
My mother sent me on a mission to Earth to find my father's killer. The man with the Kryptonite touch, Reactron. I'm supposed to be in Metropolis right now, tracking him down. Instead, a woman I barely know is doing her best to stop me and send me home. I'm Supergirl. This is my life. 
Who Is Superwoman? is a 2009 Supergirl storyline written by Sterling Gates, originally published in Supergirl (Volume 5). It follows the "Superman: New Krypton" storyline and takes place concurrently with "World Without Superman". It also crosses over into the "Faces of Evil" and "Origins and Omens" mini-events.
Synopsis
After disposing of Agent Liberty's body, Superwoman retires to her private room on New Krypton. Nobody on the newly formed planetoid knows who Superwoman truly is, or her association with Project 7734.
Superwoman then flies out towards Earth's star where she finds Supergirl bathing in the sun's radiance. The two have grown close, but Supergirl is unaware of Superwomans' true nature. Superwoman also tells Kara that many in Kandor are unhappy with Alura's decision to leave Earth. Kara says that her mother has accomplished a lot of things, but Superwoman flat out asks if Kara agrees with her mother's decisions. Supergirl doesn't answer.
Back on Earth, Agenty Liberty's body is discovered and Metropolis Metacrimes inspector Mike Henderson is called to the scene. Henderson inspects the body and goes over his notes with Daily Planet reporter Lois Lane.
On New Krypton, Supergirl returns home and has a terse conversation with her mother. Alura wants her daughter to return to Earth to capture Reactron, the man who murdered Zor-El, wife of Alura and father to Supergirl. Supergirl doesn't completely trust her mother's emotional state, but obeys her regardless. Her friend Thara, however, thinks that Alura's disregard for human life makes her dangerous.
When she reaches Earth, she finds Superwoman waiting for her. Superwoman looks more serious now than she did earlier and warns Kara that it is too dangerous for her to remain on the planet. When Kara refuses to listen to her, Superwoman punches her across the jaw.
Superwoman and Supergirl fight one another in the skies above the Earth. Superwoman wants Kara to return to New Krypton and repeatedly tells her that she's not safe on Earth. Kara fights back, but Superwoman surprises her by projecting a wall of frozen ice – a power that is not traditionally associated with Kryptonians. The frozen Supergirl drops into the sea, but before Superwoman can act further, she receives a communiqué from General Sam Lane instructing her to retrieve a "stray dog".
In Metropolis, Inspector Mike Henderson is present at the Metropolis City Hospital, where a surgical team is attempting to remove the armor from the deceased Agent Liberty. Before they can make any headway, the process is interrupted by the sudden appearance of Lucy Lane. Lane is authorized by Secret Service to retrieve Agent Liberty's body before the medical team can go any further. Henderson and she exchange words, but Lucy is undeterred.
At the Daily Planet, Cat Grant receives a surprise package in the mail. Addressed from her "tiniest fan", the contents of the package include an ugly, ratty Supergirl doll.
Sometime later, an exhausted Supergirl arrives at Lana Lang's farmhouse and collapses in her arms.
Meanwhile, Superwoman finds Reactron just as he is preparing to murder a woman named Lori in her home. As the two fight, Reactron blasts Superwoman with gold Kryptonite radiation, but it appears to have no effect. Reactron cannot understand why the Kryptonite doesn't faze her. Superwoman grabs Reactron by the throat, smiles and says "Why Reactron – whoever said I was Kryptonian?"
Reactron is ready to kill his former girlfriend, Lori Murphy, but Superwoman intervenes. The two fight one another, and Reactron now doubts whether Superwoman is actually Kryptonian or not. Superwoman tells him that she has been assigned to reign Reactron in. Rather than saving Lori Murphy however, she instead kills her, and tries to make it "look like an accident". Superwoman and Reactron then report back to Project 7734.
Supergirl meanwhile, is on the search for Reactron. Lana Lang communicates with her and tells her that Reactron was last sighted with Lori Murphy. Supergirl scans the city looking for them, while Lana tries to coordinate their exact position. Supergirl finds Murphy's apartment, but Reactron and Superwoman are long gone. She returns home to Hammersmith Tower to report her failure to her mother, Alura.
At Metropolis Police Precinct 55, Inspector Michael Henderson finds a break in the Agent Liberty murder case. Although Liberty's armor has been confiscated, his tech crew have enough information to pull an image from the armor's hard drive, revealing his murderer - Superwoman. Supergirl and Lucy Lane arrive at the precinct simultaneously. Lucy reminds Supergirl that she is on Earth illegally and now suspects that she may have been working in collusion with Superwoman. Supergirl commits herself to finding Reactron at all costs.
Supergirl is at the 55th precinct consulting with Inspector Mike Henderson as to the possible identity of Superwoman. Supergirl suspects that it might be her childhood friend, Thara Ak-Var.
Supergirl leaves and continues flying about Metropolis in search of Superwoman. She thinks that she finds her perched upon a rooftop, but this is just a trap, allowing Reactron the opportunity to ambush her. Reactron opens his chest cavity, exposing Supergirl to the Gold Kryptonite housed within. Supergirl's powers cancel out and she begins to plummet to the street below. She calls upon her training by Batman, who showed her how to deal with situations should she ever be without the use of her powers. Supergirl angles her body and uses her cape to slow her descent. She crashes to the ground, but is relatively unharmed.
Meanwhile, Cat Grant, Jimmy Olsen and Lana Lang attend a journalism awards banquet sponsored by the Metropolis public school system. Cat begins asking Lana about her "niece" Linda (who is actually Supergirl). Lana, unprepared for this particular line of questioning, begins to stumble for a response.
Elsewhere, Supergirl continues her fight with Reactron. Her powers are slowly returning to her, but so long as Reactron possesses the Gold Kryptonite, she will inevitably be powerless against him. Struggling with all her might, she charges Reactron and tears the Kryptonite from his chest cavity. Reactron begins howling in pain.
Back at the awards banquet, Lana begins bleeding from her nose. Jimmy grows concerned, but she dismisses him. Whatever is affecting takes its toll on her body and Lana collapses to the floor.
Back at the precinct, Superwoman appears and fires a deadly blast of heat vision at Inspector Henderson. As Henderson flies against the back wall, Supergirl bursts in and grabs a hold of Superwoman. She knows her true identity now. Supergirl pulls back Superwoman's hood revealing the face of Major Lucy Lane!
Lana Lang is rushed to the Ellsworth Memorial Hospital after collapsing from a seizure. Jimmy Olsen and Cat Grant are present, both of whom are worried over Lana's health.
At Project 7734, General Sam Lane monitors Supergirl's battle against Superwoman. He is distressed over the notion that Supergirl has unmasked her opponent, revealing the face of his own daughter, Lucy Lane. General Lane is confident though that his daughter will get the job done. Nevertheless, he sends Reactron out to provide her with support.
In the skies over Metropolis, Supergirl is furious at this sudden revelation. She doesn't understand how Lucy is able to imitate Kryptonian powers, but she is more enraged by the notion that this woman, who was partially responsible for her father's murder, pretended to be her friend then betrayed her. Superwoman retorts by telling her that she will finish her off, then lay the blame for everything that has happened at Supergirl's feet, including the murder of Agent Liberty.
Reactron shows up, armed with Gold Kryptonite. As before, the Kryptonite temporarily robs Supergirl of her powers, leaving her vulnerable. Fortunately for her, Inspector Mike Henderson, though bleeding to death, arrives and fires a shot into Reactron's head.
Once she regains her powers, Supergirl power-dives into Superwoman, tearing away the S-emblem on her costume, remarking that she doesn't deserve to wear the S. This prompts an unexpected reaction as Superwoman begins shrieking in pain. Her body begins to contort into grotesque positions and it becomes clear that her costume is the key to her power. The suit itself becomes unstable and explodes in a brilliant flash of light, seemingly killing Superwoman in the process.
General Lane, Codename: Assassin and a squad from Project 7734 go out to where Supergirl last fought Superwoman. Lane reflects upon Superwoman's death and the fact that she was his youngest daughter, Lucy Lane. He plans to avenge himself, citing that he has a fate far, far worse than death in mind for Supergirl.
The following day, Supergirl and Lana Lang go to Lois Lane's apartment to tell her the news. Lois doesn't believe that her sister is dead and refuses to accept the news until she has irrefutable proof. Supergirl is very apologetic, but Lois wants nothing to do with her right now. Before kicking her out, Lois asks Supergirl for a recovered piece of Superwoman's costume.
Elsewhere in the city, members of the Science Police are transporting Reactron to S.T.A.R. Labs when they get into a firerfight with the Atomic Skull and Shrapnel. This is merely a diversion however. Codename: Assassin arrives and frees Reactron.
Issues
- Supergirl (Volume 5) #37 (Who Is Superwoman? (Part I of VI) - Faces of Evil)
- Supergirl (Volume 5) #38 (Who Is Superwoman? (Part II of VI) - Clashes)
- Supergirl (Volume 5) #39 (Who Is Superwoman? (Part III of VI) - Ticking Clocks)
- Supergirl (Volume 5) #40 (Who Is Superwoman? (Part IV of VI) - Mistakes)
- Supergirl (Volume 5) #41 (Who Is Superwoman? (Part V of VI) - Daughter of Krypton)
- Supergirl (Volume 5) #42 (Who Is Superwoman (Part VI of VI) - Epilogues & Homecomings)
Notes
- This storyline is unrelated to the Prime Earth Who Is Superwoman? storyline.
Recommended Reading
Links and References
  This event or storyline is specifically related to the character of Supergirl and/or her supporting cast. This template will automatically categorize articles that include it into the Supergirl Storylines category. |
 This event or storyline is specifically related to Superman, or to members of the Superman Family. This template will automatically categorize articles that include it into the Superman Storylines category. |