Ricardo Ramirez is the young son of Los Angeles clinic doctor Teresa Ramirez, who befriends Cristóbal Rios when the crew of La Sirena travel back to the year 2024.
Ricardo is a boy living in Los Angeles in 2024 with his mother Teresa, who runs a free clinic for people without papers or insurance. He appears through the second season of Star Trek: Picard, starting when the injured Rios is brought to the clinic.
Curious and quick, Ricardo takes to Rios at once. When Teresa learns the truth about the visitors from the future, mother and son are beamed aboard La Sirena, where Ricardo is delighted by the ship and its replicator. The two are caught up in the fight against the Borg Queen and Adam Soong's mercenaries in Hide and Seek.
In Farewell, Rios chooses to stay in the 21st century with Teresa and Ricardo. Guinan later tells Picard that Ricardo grew up to be a scientist whose work helped to heal Earth's damaged environment.