きえないひとみ。 (Kienai Hitomi.)

Background
The song serves as the midpoint of the Putin-P series and the last track of part 2. It became overall the most notable song composed by Putin-P.

Following the flashbacks of Stealing is Wrong? and No Need to Worryy!!, Len is shown still hugging Rin from the end of If We Meet Again☆. After being released, Rin muses on her memories coming back and her relationship with Len; with Ronald gone and no more obstacles in their way, Rin urges Len to be with her. Len, meanwhile, said that Rin would sing a song that would destroy this world with her memories back, and that he was deceived. He deprecated himself while Sazae and Fune call him a loser and idiot.

Trying to get Len's attention again, Rin finally insults him to snap him out of his self-deprecation. Afterwards, they join hands at last and share a happy moment. Elsewhere, however, a miserable Miku mourns her loss of Ronald and then sends herself into a drug-fueled hallucination to be with him again.

In Putin-P's album Mienai yoru ni, Kienai Hitomi, a version "without" Ronald's voices, Sazae, or Fune is featured in the album.

Lyrics
Note: Putin-P often plays with the lyrics. Although the lyrics are written in the page; sometimes the Vocaloids sings it as something else. For example, although it's written 豚 (pig) Miku sings it as "Rin". In the lyrics section here, the romaji lyrics written are the ones sung by the Vocaloids.

Several changes are:
 * 豚: Pig (buta), Miku sings it as "Rin"
 * 現在: Now (genzai), Rin sings it as "ima" 今 (now)