After the treaty was drawn, Sin told the King that she believed in the same god as the Bishop, but she herself could work miracles. She turned water into poisoned wine and ferns into pork when asked to demonstrate. The king and nobles ate the enchanted food and the next day the king fell ill. Sin created an army of warriors from stone to assail the palace the next day and the weakened king fought them. The clerics came the next day and told the king he was only fighting stones and if he put the cross of Christ over his face he would see the illusion. Muircertach then put the cross over his face and saw only stones.
The clerics told him he was dying and he repented his war killings and returned home. Sin plied him with wine for seven days and told him the clerics were lying. When he fell asleep that night, she created a demon host who burnt the palace to the ground. In the morning the clerics came for his body and his wife died from grief on seeing it. Sin then appeared to the clerics and repented for the kings murder. She explained she had come to avenge the killing of her parents and sister by his hand and had fallen in love with the king. She then died and the clerics built a grave for her and a made a prayer for King Muircertach.(24)