A great evil has infiltrated the world of Ninjago, the Serpentine, a group of competing snake tribes. When strange occurrences begin to mount in their town, Jay, Cole, Zane, and Kai suspect that the tribe of the Serpentine named the Hypnobrai are to blame. But has one of their team been brainwashed? As the Serpentine battle for control of the world of Ninjago, it becomes harder and harder to tell friend from foe.