A girl falls in love with a boy.
Unable to confess, she is gifted by a deus ex machina with a text message service that tells her everything the boy does. Never minding the strange area code, the girl immediately asks for information and is overjoyed to find out that if she kills a bunch of other people who also have magical phones to predict the future.
But, the next day, when she recounts the previous day's information to the boy and was about to kill everyone, he only looks at her with a perplexed expression. After some investigation, she finds out that the boy she is stalking is also in the possession of a magical cellphone that tells the future. In fact, he is one of the people she needs to kill. He is the boy's future counterpart, who has fallen in love with the girl's own future self, who too is madly in love with him.
Hijinks ensue as the two strike up a deal to not kill each other, to murder all the other people who can tell the future. While the two chase their respective enemies, DRAMA ensues as they begin to fall in love with each other instead and question the NATURE of YANDERE.