The worst birthday of your life becomes the moment everything changes. Mizuha's drowning in the specific cruelty of being seventeen in July 2020, tournaments canceled, crushes impossible, parents checked out, when the person who was always just there suddenly isn't anymore. That's when you realize he was never just a childhood friend, and the show knows exactly how to make you feel that realization hit the same way she does.
Mizuha's seventeenth birthday arrives on the worst possible day. Her crush remains out of reach, her parents forgot entirely, and a spreading illness cancels everything she'd been looking forward to. The future she imagined for herself feels impossibly distant. Then Mizuki, someone she's known her whole life, suddenly changes everything by confessing that he wants to be more than just another familiar face. What starts as an unexpected proposition becomes something neither of them quite saw coming. Around them, three other childhood friends orbit their lives, each carrying their own unspoken feelings and quiet complications. As the world outside shifts with uncertainty, these four boys and one girl navigate the messy territory between childhood familiarity and genuine romance. What happens when you stop seeing someone as family and start seeing them as a possibility? Over one summer defined by lockdowns and canceled plans, Mizuha discovers that sometimes the person who's been there all along is exactly who you needed to find.