"From Wikipedia"

 

Hayate Ayasaki is renowned as the industry's fastest delivery boy, until his employer fires him on Christmas Eve after learning that he is underage. To his dismay, he learns that his irresponsible parents, whom he supported since the age of eight, received his monthly payment of 170,000 yen (about US$1500). Returning home, he finds that they lost all but twelve yen gambling away his salary and garnered a 156,804,000 yen debt to a yakuza, who they attempt to pay off by selling Hayate's organs as a Christmas gift.

Escaping from the yakuza, Hayate decides to kidnap a young girl named Nagi Sanzen'in for ransom money, but fails miserably by giving away his own name. In addition to that, his intended hostage mistakes his request for her to come with him to be a confession of love. Just as Hayate lies down and waits to freeze to death, a bike runs over him and he meets Maria, who is looking for Nagi. Hayate is smitten with her at first glance, though initially, he lies to Maria by saying that he didn't know anything about Nagi. Hayate's spirits lift when Maria gives Hayate her scarf, and shocked by her kindness, he goes on to save Nagi when she is kidnapped by a pair of brothers who owed money to the same yakuza. After saving Nagi, he asks her to find him a new job before collapsing from his injuries. This leads him to becoming Nagi's new butler, who must protect Nagi from all sorts of trouble while performing normal duties alongside Maria, who is Nagi's maid.