Official Rockstar Games clip, slowed down
Protagonist
Lucia Caminos
Her father taught her to fight before she could walk. She has not stopped since.
Official screenshots by Rockstar Games
Who they are
Life has come at Lucia head-on for as long as she can remember. Her father taught her to fight before she could walk, and fighting for her family is exactly what put her in the Leonida Penitentiary. Getting out again was luck rather than justice.
She came away with one rule: smart moves only, from here on. What she wants is the good life her mother has been dreaming of since their Liberty City days; the difference between them is that Lucia has no intention of waiting for it to arrive on its own.
She carries the past around with her, literally: her ankle monitor is not a costume detail but something IGN reports carries weight in the story and in how she and Jason get close.
Jason could be her way out. He could also be the mistake that ruins everything.
What is known
She is one of the two playable characters, alongside Jason.
Her ankle monitor plays a prominent role in the story and is central to how she and Jason grow close.
If they are wanted as a pair, Jason and Lucia can split up to divide police attention.
She was released from the Leonida Penitentiary before the events of the game.
“The only thing that matters is who you know and what you got.”
Official artworkOfficial artwork by Rockstar Games — “Jason and Lucia Beach” Rockstar has only published artwork of Jason and Lucia together, so this portrait is a crop of one of those official pieces.
In the game
Lucia in a Vice City pool, a cocktail on the edge. 
In the orange jumpsuit of the Leonida Penitentiary. 
Leaving a check-cashing store with a bag. 
Training in a backlit gym.
Official screenshots by Rockstar Games