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?

Teru's friend Rena reveals doubts about her engagement to successful businessman Kazuki Morizono--and for good reason! He seems to be in cahoots with nemeses Akira and Chiharu, with a hidden agenda involving DAISY's "Jack Frost" virus! How will Teru and Kurosaki deal with this newfound threat?