Ayasaki Hayate, an unfortunate high school student, spends his days working part-time jobs to support his extravagant parents. After incurring a debt of 150 million yen, they disappear, leaving Hayate to bear the burden. While fleeing from debt collectors, he attempts to kidnap a girl for ransom; however, the girl misunderstands his intentions, believing he is confessing his love. He almost immediately botches the kidnapping attempt but then manages to save her from other kidnappers, causing her to fall in love with him. The girl, Sanzenin Nagi, is actually the daughter of a millionaire family. In recognition of his services, she hires Hayate as a resident butler and even pays off the debt collectors. This is how Hayate becomes a combat butler. In order to serve and protect his mistress, Hayate's life-or-death butler life begins.