Joyû kotomi: Kuwaete ageru(1999)

Kotomi, who works at the roleplay-themed establishment "Stardust," is approached by a customer named Nakagawa. Nakagawa serves as a secretary to a businessman named Mashiba, who is suffering from a terminal illness and is searching for his long-lost niece, Reiko, in order to bequeath his fortune to her. As Reiko remains unfound—and because no one actually knows what she looks like—Nakagawa proposes that Kotomi pose as her. Kotomi is soon welcomed into the Mashiba household as Reiko, but before long, her true identity is exposed…