In the summer of 2008, Sami Brady learned that she was pregnant with E.J. DiMera's child. Sami was happy to be pregnant, but scared to be the mother of another one of Stefano's grandchildren. Sami struggled with telling E.J. about the pregnancy, even tried to convince Lucas to tell everyone that he was the father. Still, Sami ultimately decided to tell E.J. the truth. But, the day she went to see E.J., Sami witnessed the Mayor Marino's murder. She saw the killer's face. Later that night, Sami was almost shot. Fearing that she was targeted by the same man who killed the mayor, Roman sent Sami into the witness protection program. While Sami was sad to leave her family, she was relieved that she could put off telling E.J. about the baby.
Meanwhile, Nicole Walker was also pregnant with E.J.'s child. With Sami in witness protection, and Nicole pregnant with his child, Nicole and E.J. moved forward with a relationship. E.J. was thrilled to be a dad again and showered Nicole with attention for the baby. Tragically, Nicole miscarried the baby a few months after she found out about the pregnancy. Scared that E.J. would leave her if she was no longer pregnant, Nicole began an elaborate scheme of faking her pregnancy and searching for another baby to "replace" the baby that she lost.
In January of 2009, Nicole met a pregnant girl named Mia. Nicole convinced Mia to let Nicole adopt her baby. But, a few days before Mia delivered her baby, Nicole learned that Sami was pregnant. Nicole tracked down Sami, who was currently taking shelter in a convent. Nicole schemed to get Sami to give birth at a clinic in Brookville, where a doctor whom Nicole blackmailed worked. Sami and Mia went into labor at the same time. Nicole delivered Mia's baby at Mia's apartment. Sami delivered at the clinic. The baby was born with breathing problems and the doctor rushed the baby into another room to work on her before Sami could see her. While the doctor was working on the baby, Nicole went to the clinic and blackmailed the doctor to switch the babies. Then, Nicole pretended that she had given birth to Sami's baby and took the baby home. E.J. and Nicole named the baby Sydney.
Nicole and EJ had Sydney baptized under the name "Sydney Ann DiMera". Lexie and Tony were her godparents. But Nicole's plans for a happy DiMera family soon unraveled. FBI Agent Rafe Hernandez felt that Nicole was acting strangely after Grace, the baby Sami thought was her own, died. He investigated Nicole, which eventually led him to run a DNA test on Sydney. The test revealed that Sami was Sydney's biological mother. Nicole tearfully handed over Sydney to Sami and E.J., but when she returned to the DiMera mansion and heard Sami and E.J. fighting, she sneaked in and kidnapped Sydney.
Nicole and Sydney ended up in Cleveland, Ohio, where they met up with Nicole's mother, Fay, who was living there and working as a waitress. Nicole lied to her mother. She said that E.J. was abusing her, and she was simply on the run from him. Because of Nicole's stories, Fay pulled favors to get Nicole money and fake passports for both her and the baby. However, Nicole had a last-minute change of heart and decided to return Sydney to Sami and E.J. Unfortunately, while she was at the bus station, ready to turn herself in, she was attacked from behind and knocked unconscious, and Sydney was stolen from her. The kidnapper was Anna DiMera
E.J. partnered with Anna, who wanted her own revenge on Stefano and Nicole for their parts in Tony's death, to stage Sydney's kidnapping. For months, everyone in Salem thought Sydney was missing. He had Anna create ransom notes and send them to Sami. He even faked Sydney's death by placing her bloody clothes in the Salem River. Just when it looked like Rafe could not solve the crime, E.J. appeared with Sydney, professing that he had returned Sydney home. Sami was thrilled. Anna took her money and left town. And E.J. appeared to be in the clear, so he thought.
As E.J. and Sami began to bond again over Sydney's safe homecoming, Rafe had continued to investigate the kidnapping, as he was not convinced that Anna was working alone. Rafe suspected that E.J. was behind the kidnapping and tried to get Anna to confess. When she refused, he looked for clues elsewhere. Luckily, one night he happened on Nicole and E.J. having a suspicious conversation on the pier. Rafe set his sights on Nicole. He searched her apartment for something to incriminate E.J. He found the recording of E.J. confessing to paying Anna to kidnap Sydney. He told Nicole that he would grant her immunity and protection if she authenticated the recording on the record. Nicole had no choice but to agree.
Rafe rushed over to the DiMera mansion to stop Sami and E.J.'s wedding. When he played the recording for Sami, she broke up with E.J. and left with Rafe, taking her kids with her. Sydney lived with Sami and saw E.J. periodically. When Sami and E.J. reunited, Sami and Sydney moved back into the DiMera mansion.
In October 2014, E.J. was shot and killed. Wanting to get her kids away from Salem, Sami signed a contract with some Hollywood producers who wanted to make a movie about her life and moved the family to California.