Marissa Flores was a young female Human in the 24th century. In 2368, she was one of three children given a tour of the USS Enterprise-D by Captain Jean-Luc Picard as a reward for the best science projects at that year's science fair. She was the oldest of the children, but was very shy.
The tour was cut short when the Enterprise was severely damaged by a quantum filament. An injured Picard and the children were trapped and isolated in a non-functioning turbolift. In an effort to keep the younger children optimistic while they searched for a way out of the damaged section, Picard made Marissa his Number One. An emboldened Marissa responded well and helped to get the children to safety.
Approximately one-and-a-half years after the Enterprise-D's encounter with the quantum filament, Marissa was living on the USS Chamberlain after her father Peter Flores (a science officer) had been reassigned. The Chamberlain encountered a "temporal hole" which caused the crew to become frozen in time. Marissa, due to accidental exposure to chroniton particles, was immune to the temporal hole's effects.
Marissa was able to send a series of text communications to Captain Picard aboard the Enterprise-D. Captain Picard then mounted a rescue and the Chamberlain was freed. During the course of these messages, Marissa revealed to Captain Picard that she had cheated on her science fair project (in an effort to impress her estranged mother) and had been undeserving of the prize of meeting Captain Picard. Picard later assured Marissa that she still had his respect.