After the devastating events of Avengers: Infinity War, the universe is in ruins due to the efforts of the Mad Titan, Thanos. With the help of remaining allies, the Avengers must assemble once more in order to undo Thanos' actions and restore order to the universe once and for all, no matter what consequences may be in store.
When some very creepy things start happening around school, the kids at Herrington High make a chilling discovery that confirms their worst suspicions: their teachers really are from another planet! As mind-controlling parasites rapidly begin spreading from the faculty to the students' bodies, it's ultimately up to the few who are left – an unlikely collection of loners, leaders, nerds and jocks – to save the world from alien domination.