The Guild Navigator commands the Emperor to kill Duke Leto's son, Paul Atreides, because the Guild fears he may somehow threaten spice production. The execution order draws the attention of the Bene Gesserit sisterhood, since Paul is tied to their centuries-long breeding program to produce the Kwisatz Haderach, the universe's superbeing. Before Paul leaves for Arrakis, he is tested by the Bene Gesserit Reverend Mother Mohiam by being forced to place his hand in a box which induces excruciating pain. To Mohiam's surprise and eventual satisfaction, he passes the test.