Pilar Santos, a member of the Santos mob family, was sheltered from her family's shady business dealings by her mother, Carmen. Carmen sent Pilar away to boarding school because she felt that Pilar was too sweet and innocent to handle what went on in the family business. However, Pilar couldn't stay in school forever and returned home after graduation. Though Pilar understood what her family did for a living, she was convinced that her mother was a good person who wanted to get out of the business and she encouraged her mother to do so. Pilar deeply loved her mother and when it came out that Carmen had been lying to her children about leaving the business and had staged an explosion in her home, Pilar forgave her.

Though she loved her mother, Pilar detested Carmen's lover, Ben, and decided to get rid of him. Pilar knew that Ben was a liar and a thief and, after he set up Pilar's boyfriend, Bill, she knew she had to get him out of Carmen's life. To accomplish this, she decided to make it look like she and Ben were having an affair. However, Pilar's plan ended up taking a tragic turn. One night, Pilar snuck into Ben's apartment and attempted to seduce him. Ben caught on and started roughhousing Pilar to teach her a lesson, At that moment, Carmen walked in! In a state of shock, Carmen pulled a gun out of her purse and shot Ben. Believing him to be dead, they left and Carmen swore Pilar to secrecy. Soon the stress of Ben's murder became too much for Pilar and she suffered a nervous breakdown. Later, when Pilar's sister-in-law, Michelle, was accused of the crime, sPilar decided to confess. However, Carmen convinced Pilar to keep silent while Michelle went to trial: they could always confess if she was convicted. So again, Pilar put her faith in her mother.

During the course of the trial, it became apparent that Carmen was trying to send Michelle to jail and had no intentions of confessing. Finally, Pilar broke down and confessed everything in court. Unfortunately, when Pilar started to hallucinate in court, she was deemed mentally incompetent and her testimony was inadmissible. After wards, Pilar was sent to a mental hospital where her mother tried to convince her that they were never involved in Ben's murder at all. Fortunately, Pilar realized that Carmen was lying and refused to listen to her. Soon, Bill came to her rescue and broke her out of the mental institution and whisked her away to Lake Geneva to protect her from her mother. Soon, the truth came out and Carmen was exposed as Ben's killer. Pilar dealt with her mother's imprisonment and "death", then tried to help Danny run Infierno, but was infrequently seen thereafter. In September 2001, Danny mentioned that he'd sent Pilar to Europe to shield her from the turmoil of the past several months. Bill went with her, and they were happy for a time. Bill returned to Springfield in June 2002, and indicated that Pilar had broken up with him. Bill stated that the relationship had been over for some time, but only she had the guts to finally admit it. When asked how she was, Pilar's cousin, Tony, mentioned that she'd moved to Italy to study acting, and had gotten a role in an independent film.