Shawn and Gus go to visit their top suspect, the new Highmost Patriarch, Irving Parker at his Export/Import company. In the warehouse, Shawn notices shipping codes on crates from several Brazilian airports. Gus has appointments with a bunch of new clients, so Shawn is forced to tell Lassiter alone that all their evidence implicates Parker. Lassiter agrees to interview Parker but tells Shawn there is no way he's a killer and to keep looking. Shawn and Gus decide to take a different tack and investigate Holmstrom. They sneak into his house but as they are looking through his office, they hear someone else breaking in. They hide as the intruder rifles through Holmstrom's things and leaves. When they come out, they see the intruder uncovered a hidden safe but couldn't get in it. From the many pictures of Holmstrom's late wife throughout the office, they figure out the combination is her measurements and discover two lodge ledgers showing differing amounts donated to charity. It seems like Holmstrom was skimming funds from the lodge but Gus notices everything is written in doctor's shorthand and in doctor's handwriting. One of the doctors was stealing and cooking the books. Holmstrom found out about it and was blackmailing the culprit not only for money, but for the Highmost Patriarch position as well.
Back at the police station, Lassiter finally gets Parker to talk, telling him that he has no idea how Holmstrom got to be Highmost Patriarch but that he was okay with it because Arthur was a friend who had health problems which were getting worse. This would be his only shot at it. Plus, he hasn't been out of the country in years and so wouldn't have been able to bring back a snake from Brazil.
Shawn and Gus are visiting all the doctors' offices from the lodge to compare handwriting. They arrive at Dr. Downs' office and see pictures on the wall from the third world countries to which the doctor has ministered. As Gus distracts the receptionist, Shawn notices an article on powdered forms of medicine and sees a sample of Downs' handwriting. It's a match. They call Lassiter and Juliet to meet them at the lodge where Shawn explains that Downs killed Holmstrom with a powdered form of the snake venom that he put in the ceremonial hood, the venom being part of an anti-venom that Downs uses in his charitable work abroad. Shawn has solved the case but declares he never would have been able to without Lassiter's help, putting the detective in the good graces of Parker and the rest of the lodge members, rescinding his blackball status.