高中生小矶健二是一个老实内向的数学天才,夏日的一天,他应邀来到美丽的学姐——阵内夏希的家乡打工。结果发现,打工的内容竟是假扮夏希的男友。阵内家祖上曾是与德川军团殊死激战的武士家族,数百年过去,刚硬顽强的性格仍在深深植根于这个家族的灵魂之中。最初的拘谨过后,健二渐渐融入这个热闹的大家庭。 在当时的世界,一个名为“OZ”的网络虚拟平台风靡全球,16亿人为之神魂颠倒。它拥有号称世上最安全的防御系统,但其登陆密码无意中被健二所破解。神秘黑客入侵OZ,虚拟网络和现实社会顿时陷入混乱。危急时刻,阵内一家重拾武士家族的责任与荣誉,与破坏者A.I.展开了紧张激烈的夏日大作战……Kenji Koiso, an eleventh grade math genius, agrees to take a summer job at the Nagano hometown of his crush, Natuski. When he arrives, he finds that her family have reunited to celebrate the 90th birthday of the family matriarch. His job is to pretend to be Natsuki's fiancé. Meanwhile, his attempt to solve a mathematical equation causes a parallel world's collision with earth.