Amazing. These novels have turned into a series of tear-jerkers for me. All of the sweet, tender moments between Nao and Aki are almost drowned out by the painfully sad choices that the characters make or events out of their control. The premise is that Sunao has given her replica, Nao, a choice to be reabsorbed within her or to continue to live as a replica. This one ends in such a bittersweet way that is kind of painful but also kind of hopeful for everyone involved.