Ozark season 3 introduced Tom Pelphrey as Ben Davis, Wendy Byrde's brother. Ben suffers from bipolar disorder, and has an unfortunate tendency to avoid treatment for it. As he gets closer to the Byrdes' criminal operations, his erratic behavior becomes more and more dangerous for everyone. The Mexican drug cartel for which Marty and Wendy work does not play around, and the Byrdes are used to keeping their heads above water and their family alive through rigorous self-control and keeping a tight lid on anything that might turn the cartel against them. Ben just isn't capable of that level of careful behavior, and it's only a matter of time before he gets himself in more trouble than the Byrdes can get him out of.
When Ben crosses a vicious cartel lawyer, Marty and Wendy attempt to fix the problem, but Ben keeps making things worse in his attempts to make things better. Finally, Wendy takes matters into her own hands.
