As the Enterprise travels through a nebula a lifeform enters the ship and a young girl's imaginary friend comes to life. This friend gets the girl into lots of trouble and as the Enterprise traverses the nebula, it encounters a lot of resistance from some thread like substance made of Plasma. It is discovered that this imaginary friend is a lifeform and that other of her lifeform are on their way to destroy the ship. With some clever talking, Picard persuades them not to destroy the ship and it leaves.
