Day 13. News breaks that Richmond had a slew of affairs after his wife's death. Linden and Holder double-task, tracking down the former mistresses as well as security footage of the toll booths on the way from the casino to where Richmond ostensibly dumped Rosie's body. In the midst of this, Stan has an unintended run-in with Amber Ahmed (thankfully she doesn't realize who he is). After Linden and Holder's search strikes out, Holder does some math and realizes that it's more likely that Richmond filled up at a gas station that just so happens to be three miles away from the park where they found Rosie. She calls the canines on the scene, and they find Rosie's other shoe.
Though she is unaware of this, Mitch is in the processing of wallowing permanently in her grief -- to the point that she actually leaves her family. Convinced that Richmond is guilty, Linden confronts him, and overhearing their exchange convinces Gwen that not all is right. She meets up with Linden and collapses Richmond's alibi. Add that to security photo Holder scores of Richmond on a bridge leading back from the casino back to Seattle, and Richmond is arrested. As Linden boards the plane to leave for Sonoma, she learns that it's not possible for Holder to have secured such footage because the security cameras on that particular route have been out for months. As she sits trapped on the plane, Holder meets with an unseen figure and says smugly, "The picture worked." Also, Belko goes to Richmond's perp walk and pulls out a gun. Cut to black.
Previously: Linden and Holder discovered that Rosie may have been involved with an escort service called Beau Soleil. What's more, they learned that one of Beau Soleil's patrons, a john by the handle of Orpheus, has a drowning fetish. Linden sent an e-mail to Orpheus in the vain hope she might strike gold. Little did she know the e-mail would go to Richmond -- when she was in his house...
We rejoin Linden in Richmond's home office. From the eerie shadow of the doorway, he stares at her ominously, asking, "What are you doing?" She says calmly that Orpheus is an interesting screen name. He tells her the myth of Orpheus, which has particular resonance given the whole "obsessed with my dead wife" thing. Just as Richmond lowers his voice to the creepiest, breathiest register possible, Linden's phone rings. It's Holder telling her just slightly to late that Richmond is Orpheus. Linden announces stolidly that Holder is en route to Richmond's house and then slowly, steadily makes her way past the councilman. But not, of course, without a dramatic standoff on her way out. Credits.
Outside, Linden tells Holder what just went down. As usual, Holder wants to jump the gun and bring the councilman in immediately. Linden reminds him they need solid evidence linking Richmond to the crime before they can formally arrest him. They formulate a game plan to attack Richmond's alibi from all angles and see what they can come up with. Linden tells Holder to assign a unit to watch Richmond, then meet her at the impound lot to take a second look at the campaign car in which Rosie's body was found.
A little later, they meet up. Linden thinks aloud as she maps out Richmond's path to killing Rosie. Holder doesn't think it makes sense that he would use a car that could so easily be traced back to the campaign, but Linden notes the tinted windows meant that Richmond wouldn't be recognized. She opens the door and sits in the car, looking the driver's seat over once more. She tells Holder to get the gas records for the vehicle.
Meanwhile, Terry drops Stan off at the house. He is hesitant to go home, but Terry thinks it will be the best thing for the family to smooth things over. He thanks her for helping him. She says, "We're family, right?" She drives off as Stan lumbers across the street. He looks up at Mitch in the window, and they share a gaze. He walks to his car and gets in.