Death and The King's Horseman builds upon the true story to focus on the character of Elesin, the King's Horseman of the title. According to Yoruba tradition, the death of a chief must be followed by the ritual suicide of the chief's horseman, because the horseman's spirit is essential to helping the chief's spirit ascend to the afterlife. Otherwise, the chief's spirit will wander the earth and bring harm to the Yoruba people. The first half of the play documents the process of this ritual, with the potent, life-loving figure Elesin living out his final day in celebration before the ritual process begins. At the last minute the local British colonial ruler, Simon Pilkings, intervenes, the suicide being viewed as barbaric and illegal by the British authorities.
In the play, the result for the community is catastrophic, as the breaking of the ritual means the disruption of the cosmic order of the universe and thus the well-being and future of the collectivity is in doubt. The community blames Elesin as much as Pilkings, accusing him of being too attached to the earth to fulfill his spiritual obligations. Events lead to tragedy when Elesin's son, Olunde, who has returned to Nigeria from studying medicine in Europe, takes on the responsibility of his father and commits ritual suicide in his place so as to restore the honour of his family and the order of the universe. Consequently, Elesin kills himself, condemning his soul to a degraded existence in the next world. In addition, the dialogue of the native suggests that this may have been insufficient and that the world is now "adrift in the void".
Another Nigerian playwright, Duro Ladipo, had already written a play in the Yoruba language based on this incident, called Oba waja (The King is Dead).