Exhausted from the daily grind of life and work, Yoshino, a second-year working adult, finds herself at her wit's end. On one of the worst days of her life, Yoshino gets drunk and wakes up the next morning to find a mysterious boy named "Hana-kun" sleeping beside her. They end up living together temporarily, and surprisingly, Yoshino starts to feel comfortable in Hana-kun's company. As events unfold, Yoshino finds herself inexplicably drawn to Hana-kun. However, amidst this and due to a certain event, Hana-kun strangely becomes obsessed with her...