In “Better Call Saul’s” fourth season, Chuck’s death catalyzes Jimmy McGill’s (Odenkirk) transformation into Saul Goodman. In the wake of his loss, Jimmy takes steps into the criminal world that will put his future as a lawyer — and his relationship with Kim (Rhea Seehorn) — in jeopardy. Chuck’s (Michael McKean) death deeply affects former colleagues Howard (Patrick Fabian) and Kim as well, putting the two of them once again on opposite sides of a battle sparked by the Brothers McGill. Meanwhile, Mike Ehrmantraut takes a more active role as Madrigal Electromotive’s newest (and most thorough) security consultant. It’s a volatile time to be in Gus Fring’s employ, as Hector’s collapse sends shock waves throughout the Albuquerque underworld and throws the cartel into chaos — tearing apart both Gus and Nacho’s well-laid plans. While Gus changes course, Nacho finds himself in the crosshairs of deadly forces.