A mild-mannered high-school chemistry teacher (Bryan Cranston) learns that he has terminal cancer, and impulsively decides to start cooking crystal meth along with former student Jesse Pinkman (Aaron Paul) in order to provide his family with enough money for them to live on comfortably after he is gone. However, what looks like easy money becomes a nightmare riddled with complexities, moral dilemmas, murders, cover-ups, and enough life-threatening events to make terminal brain cancer the least of Walter's problems.