"Yoru wa Nemureru kai?", which translates to "Can You Sleep at Night?," is flumpool's single which will be released on February 10th, 2016. The song was composed by flumpool's guitarist, Kazuki Sakai, and their vocalist Ryuta Yamamura wrote the lyrics. It will be featured as the main theme song of the animated film "Ajin Part 1", set for release in November, as well as an upcoming "Ajin" animated TV series.

The restless lyrics, conjuring up images of uncertain and lonely days and nights, are reflected in the surreal atmosphere of the music video; with white-clad ballerinas appearing inexplicably to dance among the band members and their instruments. The words of the song alternately seem to alternately interrogate and plead with the listener. At the end, the band members are shown asleep in their car with no lights or ballerinas in sight, leaving you wondering whether it might have all been an anxious dream.