Spontaneous

During a senior calculus class at Covington High, senior student Katelyn Ogden inexplicably explodes, spraying the surrounding students and classroom with blood. The police take the class into custody during an investigation, but aside from ruling out an attack, are unable to determine the cause of the explosion. During custody, senior student Mara Carlyle suggests to the class that it could happen again, a sentiment taken seriously by her peers. Afterwards, an unknown person texts her, claiming to have had a crush on her for several years.