The Lie/I (Love) Series is a trilogy by CircusP. The third song of the series will be released in CircusP's second album and will be sung by KAITO.  It is speculated by fans that this third song is 1/4, however CircusP has never denied nor confirmed these claims.
Lie is the first song in the series, sung by Luka. The song is about Luka's conflicting feelings towards GUMI, with part of her trying to act she has no feelings for GUMI anymore, while the other half of her still loves her.
There is also another theory to this song, which was produced after the video for lie, by VocaCircus. In the video, you can clearly see Luka with Gackpo, and she says she hopes that one day she'll see his smile when he is with someone who loves him just as much as she loves him. After this, Gackpo is seen with another girl that resembles Gumi. The theory behind this is that this song is actually about Luka's love for Gackpo. After a conflict arose between the two, Luka still loves him and is wishing him happiness.
I (Love) was the second song, sung by V3 GUMI (Whisper). In the song, GUMI is aware of Luka's conflicted feelings, talking about how no matter how pointless it seems, she won't let "him" take Luka from her.