Keri Reynolds came to Llanview wanting to find her father. She immediately thought it was Hank Gannon because he had been sending her mother child support payments through the years. Keri moved into Nora Buchanan's house, after finding out they knew each other from the past in Chicago. Hank denied being Keri's father, which made her even more furious. She met Antonio, who needed credits for a Police Department job. Keri found him rude and arrogant and she didn't like his work, because he had written it long ago and the information was out of date. But soon she found that when he tried hard he could be quite charming.

Keri found out that Hank wasn't her father after all, that it was his brother R.J, who was just as surprised to find that Keri was his daughter. Antonio and R.J had a terrible time accepting that they are both in Keri's life. Antonio thought for a while they should be apart, because of his hatred for R.J., but they decided that they loved each other enough to try to make it work. But R.J. wasn't their only problem, Antonio's mother Carlotta didn't approve of Keri because she was R.J.'s daughter and wanted nothing more than to see Antonio break up with her.

Eventually Carlotta got to know Keri and realized what a nice person she was, and she gave the relationship her blessing. During a vacation to Hawaii, Antonio proposed to Keri and she accepted. But when they got home, things started to go badly. R.J. set Keri up as his alibi for the time when he was helping Allison Perkins and Lindsay Rappaport escape from prison. Antonio investigated the escape and was certain that R.J. had something to do with it. Keri felt that he was accusing her of lying when she backed up R.J.'s story and broke up with him.

Devastated by their breakup and by his accidental shooting of Ben Davidson, Antonio left town and ended up having a one-night stand with a woman he met. Antonio and Keri got back together and he was shocked when he finally met Keri's mother, Liz, she was the woman he had slept with. On top of that, Liz was pregnant and unable to carry the child due to a heart condition, so Keri became her surrogate. That meant that Keri was carrying Liz and Antonio's child, although Liz told Antonio that the child was her deceased husband Steve's. Antonio confessed to Keri about the one-night stand, but did not tell her that the woman was Liz. Antonio finally figured out that the baby was really his and decided he needed to tell Keri the truth, even if it cost them their relationship.

But Keri was having some medical problems with her pregnancy and getting upset could risk the life of the baby, so Antonio kept silent about the baby's parentage. But then R.J. learned the truth about Antonio and Liz's affair and the fact that the baby that Keri was carrying was theirs. Determined to be the one to tell Keri, Antonio handcuffed R.J. to a booth at the diner and raced to Liz's house and told Keri the truth. She was devastated by the news and promptly went into labor and was rushed to the hospital. Once there, she refused to see anyone during the delivery of the baby and agreed to see only R.J. afterward. The baby was rushed to the neonatal unit, but was soon transferred to the regular nursery, which was unusual considering how premature she was. The doctor investigated and came up with some stunning news, Keri must have been pregnant already when she tried to become the surrogate of Liz's baby in Chicago. Jamie, the baby girl she had just given birth to, was her own and Antonio's.

When Keri discovered this astonishing fact, she swore the only other person to know (Liz) to secrecy, and convinced her that they both had to leave town before Antonio found out the truth. After they left, Antonio discovered that their plane had crashed, killing all on board. He was devastated. Several months later, Antonio's brother's fiancé, Natalie, saw R.J. making odd phone calls and decided to investigate. She discovered that Keri and the baby were alive and living in Canada! Natalie confronted her and she agreed to return to Llanview. Antonio was outraged at the lies she had told, but overjoyed to see his daughter, Jamie.

The time in Canada had left Keri a bit disturbed, to say the least. She had gone from loathing Antonio to desperately wanting a future with him. She did her best to persuade him to leave his new girlfriend, Jessica Buchanan, for her and Jamie. When he refused, she barred him from seeing the child. She also began stalking Jessica, even breaking into Antonio's apartment and injuring the pet kitten he had given Jess. When Antonio gave her a harsh warning about her behavior, Keri beat herself up and then had him charged with assault. Her downward spiral continued until she was found dead after a fall from her apartment balcony.

Antonio was charged with her murder, but during the trial, it was revealed that she had committed suicide. R.J., outraged by what he believed was the product of Antonio Vega's sleazy behavior, had set it up to make Antonio look like a murderer. Antonio was cleared, and the only legacy left of tragic Keri is her beautiful daughter, Jamie.