"No matter what happens, I will protect you."

Teru Kurebayashi, a high school student, starts to receive emails on the cell phone she received from her late brother Souichirou, her only relative.

The emails, sent by a mysterious figure named "Daisy," become her sole support in life following Souichirou's passing. One day, after accidentally breaking a window at school, Teru ends up working for Tasuku Kurosaki, the school custodian.

Kurosaki is sharp-tongued and works her to the bone, but for some reason, he kindly looks out for Teru. And after meeting Kurosaki, Teru's fate starts to change drastically...

(Source: Dengeki Daisy Official Site)