Episode 20: Soul of the Guardian (2003 series)

Synopsis
The two psychotic guardians of Laboratory Five attack Ed and Al, and the confrontation forces the brothers to ponder difficult questions about life that could lead to disturbing answers.

Trivia and See Also

 * This episode is adapted from content in Chapter 11: The Two Guardians and Chapter 12: The Definition of Human.
 * Episode 8: The Fifth Laboratory (2009 series)