The curse first manifested in a sweeping death of all the crops, after which the city's water supply turned to sand. Arthur was offered a chance to lift the curse by Anhora, the Keeper of the Unicorns, if Arthur could prove himself pure of heart. Arthur initially did well, releasing a peasant named Evan who had attempted to steal a bag of grain from the Castle stores despite King Uther's orders to execute all looters. His mercy earned Camelot its water back.
Arthur later failed a test when he came across the same peasant in the forest, discovering that he was nothing but a thief who had lied. The peasant insulted and demeaned Arthur until the Prince attacked and tried to kill the man, at which point Anhora appeared and told Arthur that his willingness to kill a man who had wounded his pride would cost Camelot dearly. Soon after the encounter, Uther instructed Arthur to give an order to stop all rations to the residents of Camelot, but Arthur refused to carry out the order.
To save the city, Merlin then sought out Anhora, begging the sorcerer to give Arthur another chance. Anhora obliged by offering to let Arthur prove himself in the Labyrinth of Gedref, in which Arthur faced a difficult choice. He and Merlin were set before two goblets, one containing water and one containing a deadly poison; all of the liquid had to be drunk, but each man could drink from only one goblet. On Merlin's suggestion, Arthur poured the contents of one goblet into the other, combining both into one goblet and (against Merlin's objections) drinking all of the liquid himself.Anhora explained to Merlin that Arthur had not died because the second goblet had contained not poison but a sleeping draught. In his willingness to die for his people and for a friend, Arthur had proven himself pure of heart, lifting the curse from Camelot. Later, in the forest outside the city, Arthur and Merlin laid the unicorn's horn to rest, and saw the resurrected animal between the trees (The Labyrinth of Gedref).