In the third season, two airplanes they clash because of the father of Jane, his daughter died in the second season of the series for the use of drugs. A pink soft toy burned falls into the pool of Walter, was probably of a child died in the plane crash. Meanwhile, Walter lives in his home alone because his wife she moved with their children to her sister, to give time to Walter leave home. Meanwhile, Jesse is in a rehabilitation center to fight his drug addiction. Walter decides, therefore, to stop the production of meth and he tells Gus, but Gus offers him three million dollars for three months of work in his laboratory.. And he accepts.
In the fourth season, Jesse has abandoned the production of meth and Gus entrusts to Walt the help of chemical "Victor". Victor learns soon the recipe of Walter enough to want to take his place. Heisenberg (Walter), prepares a bomb. He goes to the rest house where he finds Hector Salamanca and convinces him to ally themselves against Gus. Gus arrives at the rest house and enter in the room of Hector Salamanca, sits down in front and, while Tyrus prepares a lethal injection, Gus insults the old boss for talking to the DEA and asks him to look into his face for the last piece. Hector then starts to ring the bell to activate the bomb. For Gus there isn't longer hope of salvation, falls to the ground and dies.