Lauren was the niece of Emily Valentine who went trick-or-treating along with her twin brother Drew under Emily's care. They came to the Walsh Family House, dressed as ghosts, at which point Brandon Walsh tried to frighten them with his vampire teeth and costume.
They had to use the restroom and later finished their trick-or-treating with Brandon and Emily. They ended up getting lost, causing Brandon and Emily to become frantic, only to find them back at the Walsh Family House. They implied that Brandon and Emily had gotten lost.
Later, when Brandon was driving them home, they encountered David Silver and Scott Scanlon, who were laying in wait for an egg fight. They laughed when Emily insulted them, at which point David and Scott began throwing eggs at their car. They are later said to be safe and sound at their home.