在这部手机男友片中,最近，在女高中生之间，流行着一款名叫《手机男友》的手机游戏，在游戏中，女生们可以根据各自的喜好选择不同形象的男生作为自己的虚拟男友，通过按键操作来增进跟他们之间的感情。长内真由美（中川美树 饰）是这款游戏的重度痴迷者，对于她来说，手机中那个英俊帅气的男生早已经超越了虚拟影像，成为了生活中不可缺少的一部分。
然而，从今往后，真由美将再也无法见到自己深深迷恋的虚拟男友了，因为她死了。真由美死前留下的讯息暗示了这场悲剧和《手机男友》有着千丝万缕的联系，为了查明好友的真正死因和事件的真相，上野里美（川岛海荷 饰）和小野寺由香（朝仓亚纪 饰）等人展开了对事件的调查。
High school student Ayumi kills herself and leaves behind a cryptic message that says "will be killed by boyfriend." Ayumi's classmates Satomi and Yuka investigate her suicide and quickly links her death to a popular cellphone dating simulation game called Keitai Kareshi. The main features of the game include a 'love gauge' that determines how well the player is faring and the ability to chat with other players. Satomi, Yuka download the game to their phones and begin interacting with their new virtual boyfriends. Soon after, Satomi shares the game with her co-worker who -- not long after the love gauge on her cellphone hit zero -- dies from electrocution. Meanwhile, Yuka sends the game to her manager who turns up dead the following day following a mysterious accident. The mystery deepens as Satomi discovers the image of Naoto, a senior student whom Satomi secretly admired, on her friend Hisami's cellphone.
纯爱~女生GAME~。小木茂光终于摆脱了龙套身份来了一把配角……。手机男友，总带有一些纠结。为什么女主的妈玩手机男友没有出事 ？。
