Robo, a beloved Great Dane, is tricked out of the embrace of his human family and then is horribly altered by a scientist who rebuilds him with technology never seen before. It leaves Robo a genius, almost immortal and with powers beyond explanation. But the suffering Robo experiences changes him—driving him insane with the sole mission to destroy all humans, especially those who have tortured and hurt dogs. Meanwhile, Blue, a scrappy alley dog, is trapped in a shelter, when she captures the attention of another scientist desperate to stop Robo from his path of destruction. Her mission: save human civilization and the packs of dogs she's grown to love.