After embarking on a life-changing field trip, a group of whip-smart students fight to save humanity from an army of ruthless drones.

Some students travell to the launch of the 'genie orbs', a new class of robot designed to clean up the environment. When the artificial intelligence-powered orbs are introduced by tech billionaire Dalton Monkhouse (Robert Sheehan), they appear to vaporise everyone in the audience. Thousands of identical events occur all over the world. The students just manage to make it back through the carnage to their rackety old school bus and head home in search of answers, only to be met by a mysteriously empty world.

Realising they are going to have to fight back, the students embark on a road trip to find Dalton Monkhouse and get some answers to what has happened to their families. Along the way, they are confronted with a succession of increasingly intense challenges - from towering junk monsters to a damaged orb with a seemingly-personal vendetta - and the characters overcome their personal differences and private demons to become an improvised family.