Arato's life has changed dramatically since meeting Lacia. There was the excitement of living together coupled with the experience of being the owner of a high-functioning hIE. While there were incidents such as her kidnapping, there were others in which he willingly dove into danger with Lacia's help. And now our story is about to progress to the next stage.

Kouka, Snowdrop, Methode... Known collectively as Red Boxes, what did meeting these high-functioning Lacia-class hIE's bring to Arato and Lacia's relationship, and what is about to come? Slowly but surely, Arato's world is beginning to change.

The world is changing. What exactly are the Lacia-class hIE's striving to accomplish? Future possibilities begin to slowly take shape. What is in store for humanity?

What is Lacia? Will humanity ever be able to provide an answer? A new era brought on by highly intelligent AI. Caught in the middle of this turmoil, Arato takes Lacia's hand with some reservations. Will his decisions lead to the end of humanity? Or the start of a new beginning?