As the God Emperor Leto and his entourage march toward the city of Onn along the Royal Road, Moneo walks beside the Royal Cart anticipating a meeting with petitioning Museum Fremen. Suddenly, the approaching petitioners shed their colorful pilgrim robes to reveal black uniforms and rapidly alter their faces into likenesses of Duncan Idaho through Face Dancer mimicry. Chaos breaks out as Fish Speaker guards clash with the disguised attackers using stunclubs, knives, and lasguns. Duncan Idaho, having stripped off his uniform prior to the encounter, fights alongside the guards while naked, unwittingly rendering himself distinct from the mimics. Leto drives his cart like a battering ram into the attackers before sweeping across the river canyon to a high viewpoint, amused by the clumsy assault launched by the Tleilaxu.
Following the skirmish, Leto, Moneo, and Duncan inspect the aftermath where over thirty members of the royal party and all fifty Face Dancers lie dead. Leto falsely claims immunity after a lasgun beam strikes his cart canopy, while Duncan advocates for protective shield belts despite their prohibition and catastrophic interactions with lasguns. Moneo confesses responsibility for arranging the encounter, having been deceived by the impostors who replaced the original Fremen delegation. Although the Tleilaxu plot failed to eliminate their targets, Leto recognizes it as part of a deeper snare and determines to respond with calculated unpredictability to intimidate his subjects and adversaries alike.
News arrives from the Bene Gesserit regarding the Tleilaxu threat, though Fish Speaker guards had initially dismissed the warning. To project absolute authority and signal the Tleilaxu without offering explanations, Leto orders the public flogging and expulsion of the Tleilaxu Ambassador during an upcoming audience. As fresh supplies and a replacement cart canopy are delivered by ornithopter, Leto commands Moneo to clear away all evidence of the carnage before entering Onn. Before sending Duncan ahead to scout, Leto shares a cryptic parting instruction, commanding Moneo to tell his daughter Siona that she mirrors the unconscious force within him that preserves his memory of humanity and love.