It's been a long, slow, dark road for Walter White, one Breaking Bad creator Vince Gilligan hopes has been interesting for viewers to follow.
But how did we get here? How did the show arrive at a point where Walter orders Jesse to kill an innocent man in order to save their lives? The latest trailer for season four - which premieres on July 17 - takes us back to the beginning of this wonderful series.
Sit back and watch the evolution of Bryan Cranston's character now: