A dysfunctional family of superpowered adopted siblings—led by the guilt-ridden Spaceboy, the bitter Kraken, the reality-bending Rumor, the spirit-channeling Séance, the time-traveling Boy, and the forgotten Vanya—reunites after the death of their abusive alien father, Sir Reginald Hargreeves. As they gather to bury him, Number Five arrives from a apocalyptic future, warning that the world will end in less than twelve hours. The siblings must overcome decades of resentment, trauma, and infighting to stop the mysterious Conductor and his Black Orchestra from unleashing Vanya's suppressed power as the world-destroying White Violin—before a lunar meteor finishes the job.