Merlin,an immortal witch from seven deadly sins in witch trial.Executed by eternal fire,the biggest question is how long will she struggle and suffer the pain before the fire consumed her body if her "infinitive magical power" can be exhausted and her body is not invulnerable.IF she can be hurt,she will be killed mercilessly by fire in that condition.And it will be really her nightmare to see herslef slowly burnt into bones and ashes.