After orphan Teru Kurebayashi loses her beloved older brother, she finds solace in the messages she exchanges with DAISY, an enigmatic figure who can only be reached through the cell phone her brother left her. Meanwhile, mysterious Tasuku Kurosaki always seems to be around whenever Teru needs help... Could DAISY be a lot closer than Teru thinks?

When Teru mistakenly tells Kurosaki to disappear from her life, she gets consumed by guilt because he actually vanishes. In order to get him back, she'll have to uncover his past relationship with her brother along with the exact details of his crime...