Unable to confess, she is gifted with by a deus ex machina with the boy's phone number. Never minding the strange area code, she immediately calls him, and is overjoyed to find out that he has a crush on her as well.
But, the next day, when she recounts the previous day's confessions to the boy, he only looks at her with a perplexed expression. After some investigation, she finds out that the boy she called is not the same boy she fell in love with. In fact, he doesn't exist in this universe at all. He is the boy's alternate universe counterpart, who has fallen in love with the MC's own AU self, who too is blissfully unaware of his crush.
Hijinks ensue as the two strike up a deal to give each other their darkest, most private secrets in order to equip the other with the weapons they need to conquer the heart of their other selves. While the two chase their respective loved ones, YURI ensues as they begin to fall in love with each other instead and question the NATURE of SHOUJO AI.