Hannah Lewis is the love internet of Matt Saunders from My Super Ex-Girlfriend.
She was Matt's co-worker who is secretly in love with him after they work together for 3 years ago. She was dating a guy name Steve who was the underwear model.
As Matt and Hannah's friendship develops further, and after becoming aggravated with Jenny's escalating jealousy, Matt ends the relationship.
An enraged Jenny vows to make Matt regret the decision, using her superpowers to publicly embarrass him, throwing his car into space and eventually causing him to lose his job as an architect when she strips him naked during an important meeting.
While Matt's having a hard time with Jenny Johnson a.k.a. G-Girl, Hannah was having a hard time with her boyfriend since she caught him in bed with a women.
So, she break up with Steve after realizing that Steve wasn't the one and fall in love with Matt.
After she and Matt confessing their feelings, they kiss and end up in bed.
Jenny (as G-Girl) discovers them in bed the next day. Enraged and jealous, she attacks the pair with a great white shark.
Angered, Matt contacts Professor Bedlam and agrees to help him defeat her, as long as Bedlam retires from being a supervillain.
He instructs Matt to lure Jenny to a meeting where she can be exposed to another meteorite that will draw away her powers, leaving her a mere mortal. Then, Matt agrees and meets Jenny for a candlelit dinner at his apartment, under the pretense of wanting to resume their relationship.
Then, Hannah arrives to see Jenny sitting on Matt's lap. The two women fight, and in the struggle Jenny's superhero identity is revealed to Hannah. Bedlam's trap is sprung, and the energy that gave Jenny her powers is drained back into the meteorite, incapacitating Jenny.
Professor Bedlam appears, but reveals that he has no intention of keeping his promise to retire from villainy and plans to take the powers for himself.
While he and Matt fight, Jenny crawls to the charged meteorite attempting to regain her powers. Hannah intervenes just as Jenny grabs the meteorite, which explodes in a burst of power.
Both Hannah and Jenny are catapulted off the roof, apparently to their deaths; Jenny appears within seconds, powers restored, threatening even more mayhem.
Only the unexpected reappearance of Hannah, who was also exposed to the meteorite's energies, and now possesses the same powers as G-Girl, saves Matt.
The second fight between Hannah and Jenny is a full-on super-brawl, destroying part of the neighboring properties. Finally, Matt reasons with them both and they cease fighting.
Then, Matt tells Jenny that Professor Bedlam is her true love which Jenny agrees and she embraces her former nemesis.
The next morning, Matt and Hannah meet up with Professor Bedlam (now just "Barry") and Jenny.
As cries for help are heard from afar, Jenny and Hannah, who have become partners in crime-fighting, take off to tackle the emergency. Matt and Barry are left holding their girlfriends' purses and clothes, and leave to have a beer together.
At the end, it's unknown if she's still dating with Matt or married.
- Hannah's powers are very similar to the DC comic book heroine, Supergirl.