|Mother of Thalia and Jason Grace|
|Appearances|| The Titan's Curse (mentioned)|
The Sword of Hades
The Lost Hero (mentioned)
Ms. Grace was briefly the lover of Zeus (and later, his Roman form Jupiter). She was the mother of Thalia and Jason Grace. Thalia described her as being an alcoholic and she later died in a car accident.
Ms. Grace dated Zeus during the eighties, when she was a TV starlet with a "big poofy eighties hairdo." Their relationship resulted in the birth of Thalia. However, Zeus eventually had to leave her to return to his duties on Olympus. Ms. Grace didn't take it well, as she felt that she was better than most people because she had attracted the king of the gods. This resulted in an inflated ego and she eventually turned to alcohol, eventually ruining her life and career. This lead to many arguments with her daughter, Thalia.
Seven years after Thalia was born, Zeus returned to Ms. Grace (this time in his Roman form; Jupiter), which Thalia thinks was because he felt bad for the way her life was going. He stayed for awhile and Ms. Grace improved her behavior, loving the attention Jupiter gave her. The two also had another child, much to Hera's anger. In order to appease the goddess, Jupiter and Ms. Grace decided to name the boy Jason, after Hera's favorite mortal. However, Jupiter eventually left and Thalia only stayed with her mom because she didn't trust her alone with Jason.
Two years after Jason was born, Ms. Grace took the family on a vacation near the Wolf House. Ms. Grace told Thalia to go get the picnic basket from the car. While she was gone, Ms. Grace offered Jason up to Hera as a peace offering. When Thalia returned, Ms. Grace told Thalia he was gone as she cried on the stone steps. Thalia had thought her mother had finally lost her mind and searched for her brother, eventually calling the police on her own mom. Ms. Grace was questioned for a long time, but she wasn't arrested and turned on Thalia, saying she betrayed her. The mother and daughter argued before Thalia eventually left home.
Ms. Grace only got worse from there. She developed a drinking problem, which grew progressively worse over time, ultimately resulting in a car accident that took her life, two years before Thalia was awakened from her tree by the Golden Fleece.
Thalia, Percy, and Nico are in the Underworld on a mission for Persephone to recover Hades' stolen sword. When traveling through the Fields of Asphodel, Thalia looks around at the faces, looking for her mother. Also, Melinoe appears to Thalia as Ms. Grace, yelling at her for abandoning her. Thalia is shocked by this, and protests that her mom had abandoned her. Percy manages to destroy the illusion by out smarting Melinoe and Thalia is very shaken up from the experience.
When Thalia is reunited with Jason, she explains what happened the day he disappeared and mentions the reasons she ran away from her mother. She also tells him how she died two years before Thalia was awoken.
Ms. Grace was a very self-centered person. She believed that her looks and talent was enough to get her anywhere she wanted to go. Even before she met Zeus, she already had some serious problems, including drinking and pulling stupid stunts to get her face in the tabloids. After Zeus fell in love with her the first time, she felt more like she had made some kind of grand achievement and her ego grew. So much so that when he left, her more serious flaws emerged and she turned to drinking. When Zeus returned as Jupiter, she relished in the attention he gave her and improved until he left once again, causing her downward spiral. When Thalia called the police on her after Jason vanished, Ms. Grace turned on Thalia, believing she had betrayed her own mother instead of siding with her and agreeing it was the right choice. Her bad habits eventually lead to her death in a car accident as she had been drinking.
She is described as being a tall, beautiful woman with a big poofy eighties blonde hairdo and blue eyes.