In Episode 11 of AI no Idenshi, the story deals with the complexity of identity and the ethical implications of copying neural networks. A new character, Tu Fui, is introduced in the episode, who claims to be Risa's sister.

The episode begins with a flashback to Risa's past, revealing that she survived a hot air balloon accident in which her mother died. Dr. Sudo was the one who reconstructed her body and neural network. The episode then shifts to the present, where Risa receives a surprise visit from Tu Fui, who claims to be her sister from India. Tu Fui explains that her father adopted her and raised her in India, but he passed away six months ago, leaving her alone.

Tu Fui moves in with Risa, and the two quickly bond over shared experiences and family history. However, the situation takes a dark turn when authorities arrive to arrest Tu Fui. It turns out that Tu Fui is not Risa's sister but a copy of Risa's neural network. Tu Fui confesses that she killed her adoptive father in India and came to Japan to replace Risa, but she couldn't do it because Risa had done nothing wrong.

The episode also sheds light on Dr. Sudo's past, revealing that he was offered participation in a clinical study on neural networks to cover the costs of his son's treatment. It is hinted that Dr. Sudo's mother might also have a copied neural network somewhere.

Toward the end of the episode, Dr. Sudo is approached by a representative of Michi, the super-AI, who offers to help him search for the copy of his mother's neural network in exchange for his participation in an examination committee for Michi's major update. Dr. Sudo accepts the offer and informs Risa that he is leaving Japan to find his mother, thanking her for her support.

The episode ends with Dr. Sudo's departure, leaving Risa alone as she reflects on her own identity.