Kanata Kitami, an unpopular high school loner, has been in love with his cheerful and popular childhood friend Marika Chitose for years but lacks the courage to confess. After making a joking wish upon a shooting star to understand people's feelings like in a dating sim game, he wakes up with a bizarre new ability: he can see floating numerical "love meters" above the heads of all the women around him, from his classmates to his own mother. Confused but hopeful, Kanata immediately checks Marika's meter, expecting to find a high number that reflects her famously kind demeanor toward him. Instead, he is horrified to discover her meter is not just low, but completely broken, showing a negative value so extreme it appears to have melted and plummeted off the scale.

The series is set in a contemporary Japanese high school and follows Kanata as he navigates this surreal romantic comedy scenario. While the love meter should theoretically make his love life easier, Marika's malfunctioning reading creates a baffling mystery. Her meter indicates she despises him, yet her actions are overwhelmingly affectionate, leaving Kanata confused and paranoid about her true intentions. The truth, which Kanata slowly uncovers, is the opposite of what the meter suggests. Marika's love for him is so intense and obsessive that the meter cannot process the extreme emotion, causing it to short-circuit and display a catastrophic negative reading. Her seemingly perfect exterior hides a secret obsession, as her room is plastered with pictures of Kanata and she keeps him as the background on her phone.

As the story progresses, the narrative expands beyond the central misunderstanding. Kanata begins to realize that other girls in his class, including the aloof Sayuki Toyotomi and the cheerful rom-com enthusiast Kokona Mikasa, also have fluctuating meters, revealing hidden feelings and crushes he never suspected. Key narrative arcs involve Kanata learning to interpret the meters correctly, dealing with the comedic complications of accidentally raising other girls' affection levels, and his ongoing struggle to reconcile Marika's contradictory signals. The series builds toward Kanata accepting that the malfunctioning meter is not a sign of hatred but a testament to a love so powerful it breaks reality itself, forcing him to find the courage to act on his own feelings without relying on his supernatural crutch.