 In the letters, a powerful Great Light Other promises a human that they will turn him into an 'Other', which the human deeply desires.However, as far as the Others are concerned this is impossible and as such, the Light Other is in danger because refusal to fulfill this human's request means that he or she will dematerialise in the Twilight.Anton is assigned the case and goes to the Assol, a rich district in Moscow where the letters came from.