True Q

The Federation starship Enterprise brings aboard a young Starfleet intern, Amanda Rogers, who plans to study biological sciences under Dr. Crusher.

Picard argues with Q about the morality of his decision, while Q points out the responsibility that the Continuum has to govern their omnipotent powers and the people who use them (Amanda could accidentally destroy the entire galaxy).

Eventually Q tells Picard not to worry, that he's decided Amanda is Q, and as such she has a choice: either to return to the Continuum, or she can choose to live as a human, but if she does she must voluntarily suppress her powers and not use them.

Q warns Amanda that it won't be as easy as she thinks, revealing that her parents were given this choice but were unable to resist using their powers, resulting in their execution by the Continuum as punishment.

As Amanda contemplates her choice, the ship receives a distress call from a nearby planet where their ionic anti-pollution systems are failing rapidly, which would flood the atmosphere and block out the sun.