She is wanted by the Coalition of Planets for a list of crimes, including theft and at least five murders. She is also known to be very good at deceiving people. She mainly traveled with two accomplices, Bordal and Jannick, since she felt that two is all that is needed, and saved them from dangerous situations on at least one occasion.
She and her accomplices went to an unnamed planet, is a member of the growing Coalition of Planets, where they broke into the main town's vault of valuable artifacts, which included a long-range communication device. She found a long-range communication stone and placed it onto the device, where it activated. Her consciousness was switched with Dr. Jennifer Keller's in Atlantis. Not knowing what had happened, and fearing she would be caught, she stabbed Dr. Radek Zelenka. She discovered through her reflection that she was in someone else's body. When she was called upon to perform surgery on Zelenka, she claimed to not be feeling well, and was sent to recover in her quarters. There, she decided to leave Atlantis via a Puddle Jumper, and armed herself. She discovered through Dr. Rodney McKay that she didn't have the Ancient Technology Activation gene to fly it. She attempted to seduce McKay to fly for her, but after realizing he won't fly it, she attempted to kill him, but is stunned by Ronon Dex. Soon, they discover "Keller's" true identity.
Knowing that she and Keller swapped places, they wanted her back, and she seemed happy to help them get to the planet, but wanted their promise that the Atlantis expedition will not hunt her down. They agree to the terms and sent her to the planet that she last remembered. However, after realizing that the planet's authorities sentenced Keller to execution, and that Bordal and Jannick freed her, Neeva fled and found the three, but fails to convince them of the strange circumstance. The four were then ambushed, where Keller escaped, Bordal was killed, and Neeva was shot by a villager. Fortunately, she was saved before the villager finished her off. She was sent to the village to be operated on.
Meanwhile, Keller, in Neeva's body was tracked down by Jannick and was about to kill her for trying to get him killed, when Lt. Colonel John Sheppard's team managed to shut down the communication device, by Ronon shooting it. The two consciousnesses were transferred back into their own bodies again. However, Neeva watched Jannick holding her at gunpoint, and failed to convince him that she is the real Neeva. After the events, Major Evan Lorne and his team returned to the planet to look for her body, but found nothing. There was also no trace of Jannick. She is presumed dead, but because it is unconfirmed, there is currently a warrant out for her arrest on all Coalition planets. (SGA: "Identity")
Behind the scenes
Despite being called Neeva Casol in the subtitles for the episode "Identity" as well as in a video interview with the actor Dawn Olivieri published on the official MGM website, the character's name is spelled Neela on the episode summary on both the MGM and Sci-Fi Channel websites. Though the reason for this is unknown, it's possible that the character was originally named Neela or that the author of the website material simply made a spelling error.