|“||We've invited all these people. Might as well give them a show.||”|
Abigail Callahan is the daughter of Robert Callahan.
Not much is seen of Abigail, but from her father's dedication to her, she appears to have been a good daughter a dad would be willing to fight for, and she and her father were very close. As a child she might have had a wild streak due to wanting to participate in bot-fighting, as well as having an interest in technology. She is very brave and dedicated to her job and science, willing to go where no one has gone before.
Abigail is a slender young woman with large blue eyes that resemble her father's and chestnut brown hair that she keeps in a simple ponytail. She is only ever seen in her pilot suit, a white skin-tight garment with red accents and white armor on her chest and shoulders, along with a matching white pilot's helmet. On the side of her helmet is her last name, printed in all caps.
Abigail helped with the testing for Alistair Krei's teleportation technology. In the recordings of the test, she is seen hugging her father Robert Callaghan and going into a shuttle that would be sent into two portals: one for entering and another for exiting. However, the system began to glitch; nevertheless, the test went forward and Abigail was sent into the portal, but the second portal from where she was supposed to exit from exploded, leading to the shutdown of the facility while stranding Abigail in a mysterious void within the portal.
Following the events of Abigail's disappearance, Robert continued his days as a professor at the San Fransokyo Institute of Technology, mentoring a group of intelligent individuals. Amongst his prodigies is the esteemed Tadashi Hamada, whose younger brother, Hiro, greatly desires acceptance into the school. To do so, Hiro invents the Microbots — miniature bots capable of manifesting anything their host commands — and presents them at the school's annual science fair. After witnessing Hiro's creation, Robert steals the inventions and covers his tracks by setting the school's showcase hall ablaze; the fire causes an explosion which kills Tadashi, who entered the burning hall intending to rescue Robert. Meanwhile, Robert is presumed dead (with the world believing he was also killed in the fire) and abandons his true identity, becoming a stoic, ruthless villain by the name of Yokai, and uses the Microbots to reassemble the portal that took Abigail, in hopes of using it to kill Alistair Krei as revenge for the former's demise.
Meanwhile, Hiro, his robot companion, Baymax, and Robert's former students, rally together to form a superhero team in order to capture Yokai and bring him to justice. After defeating Yokai, who's true identity is eventually revealed, Baymax senses life within the portal, and reveals it to be a living female in hyper-sleep. Knowing it has to be Abigail, Hiro travels inside with Baymax to rescue her, and finds her with help from Baymax's scanners. When Baymax's armor is damaged during their way back, Baymax sacrifices himself to save Hiro and Abigail, who both then make it back to earth. As Abigail regains consciousness, she is wheeled towards a waiting ambulance, while Robert is arrested for his crimes.
- In the Big Hero 6 mange, Abigail is much younger than she is in the film. Her mother's name is also mentioned in the manga, which is Sarah.