“The Byrde family’s relationship with each other, their relationship with Ruth, her relationship with Wyatt — you want all these themes pointed at each other, and more intensely, as you go forward.

The action picks up where Season 3 ended, in the moments after Mexican cartel kingpin Omar Navarro (Felix Solis) executed his attorney Helen Pierce (Janet McTeer) in front of his money launderers Marty and Wendy Byrde (Jason Bateman, Laura Linney) — now deeply enmeshed in his deadly world while continuing to run their sketchy riverboat casino operation in Missouri.

Back home, their 14-year-old son, Jonah (Skyler Gaertner), still seething at his parents, particularly Wendy — he shot out the windows in their lakefront house in last season’s finale — offers to launder money for the drug-distribution partnership between Ruth (Julia Garner), her cousin Wyatt (Charlie Tahan) and his much-older girlfriend, bat-s–t-crazy Darlene Snell (Lisa Emery).

“At the same time, Ruth is trying to figure out how to run her business with Wyatt and Darlene and is getting a little wary of Darlene … who is someone who is obviously fairly crazy but at the same time she’s got this very strict moral code she lives by,” Mundy said.

And, as the first part of Season 4 progresses, Marty — and, particularly, Wendy — try to consolidate their political clout across the region, luring Big Pharma CEO Clare Shaw (Katrina Lenk) into their money-laundering web