During her time working at the alien hunting organisation Torchwood, Suzie was a reserved introverted woman. Due to her apparent empathy she was able to use an alien glove the organisation had found to revive the recently deceased for short time spans. Slowly becoming obsessed with the power of the glove, she quickly was willing to betray her coworkers and after experiencing the afterlife once, she became desperate to avoid her own death at any cost.
Suzie secretly became a serial killer, and fatally stabbed two women and a man using a blade made of the same metal as the Resurrection Gauntlet because she knew that frequent murder victims would give her an excuse to use the glove on them for testing purposes. She wanted to practice as much as possible to learn how to revive people completely, but before she had success police officer Gwen Cooper deduced that she was the murderer and confronted her. In a standoff with Gwen, Suzie laments how filthy humans and the planet Earth is, when her boss, Jack Harkness appeared and attempted to stop her but was shot in the head by Suzie. When Jack was revived due to his immortality, Suzie ultimately realized her plan had failed and killed herself. Gwen was hired at Torchwood to fill the gap left by Suzie, but unbeknownst to Torchwood, Suzie had prepared a backup plan for this scenario long in advance.
They Keep Killing Suzie
Suzie had manipulated the subconscious of Max, a friend she knew from a discussion group called Pilgrim to go a killing spree in case she disappeared. Max targeted other members of Pilgrim and wrote "Torchwood" on the walls in their blood, leading Torchwood to discover the connection to Suzie and use the glove on her to get information, as she had planned. She also had programmed a secret voice activation code to lock the Torchwood base, which would then be activated by her imprisoned friend reciting a poem. When she was revived by Gwen, the gauntlet kept her alive permanently, slowly draining Gwen's life, but Suzie kept that a secret, pretended to be on her side and persuaded Gwen to drive her to her sick father in a hospital, who expressed fear at the sight of his daughter. Suzie then murdered her father by ripping out his life support chords as revenge for trying to force her to be perfect when she was younger.
After they had left, the base went to lockdown as planned, but Jack managed to escape and track them both down. By the time he arrived he wasn't able to kill Suzie, who had practically become immortal due to constantly draining energy from the now dying Gwen. The only way to kill Suzie was destroying the gauntlet for good. After the Torchwood team took that sacrifice, Suzie, in her last breath, revealed to Jack having experienced the nothingness of death and that out there in the darkness something was coming for him.
Long Time Dead
When the headquarters of Torchwood were destroyed, following the events of The 456 Incident, a young worker near the scene was murdered, and Suzie's body was reportedly missing. It was revealed that she was revived a second time after her corpse interacted with alien technology. Suzie murdered the worker and escaped the scene going on a killing spree under the alias "Sue Costa" while learning of the respective fates of her former coworkers. After being identified as the murderer yet again and receiving a threatening phone call from Jack Harkness, Detective Tom Cutler, her previous partner, convinced her to return to the hub in an attempt to negotiate, but a bomb destroys the hub again, and Tom and Suzie are killed. Andy dejectedly finds their charred remains.
- Her role as the antagonist in the first episode was well hidden by her actress Indira Varma being credited in the intro and advertisements, indicating she would be a regular.
- Suzie was scheduled to be a more recurring character, but her appearances were cancelled when Indira Varma became pregnant.