Wensicia's plot to assassinate the Atreides heirs fails, but provides Leto an opportunity to fake his own death and buy time to overcome Alia. Alia's madness reaches its peak as Baron Harkonnen's grip on her consciousness strengthens and a civil war brews with the rebel Fremen. Leto returns from the deep desert, having used sandtrout — the larval form of Arrakis' sandworms — to acquire the superhuman speed, strength, and invulnerability of the sandworms themselves.