Mike goes to see Zach again, now that he's remembered how he totally sent Zach to kill Paul, and in like one second Zach's like, "Oh, yeah! I totally shot Paul. It was awesome!" Mike's like, "Sometimes when we're crazy on drugs, we do things like shoot our adoptive/kidnapper parents." Zach goes full Intervention on his ass, all, "I don't even know what drugs are! You're being crazy! Get out so I can do some drugs!" Mike wants to put him in rehab, but Zach is A) An addict and B) Thinks that would make it easier for Paul to find him and exact revenge, either by sending him to jail or stabbing or toastering him. Mostly A.
So after Zach does some creative reinvention as far as how he ended up in Mary Alice and Paul's care, which was just odd that he would be deluded about how all that went down since it's the only thing that ever happened to him, Mike leaves again to brood some more while Zach does a bunch more drugs. It's so funny that they've hit the ceiling on the normal amount of Zach crazy and now it's like the only way to make him crazier is to add drugs to the mix. But it's also not that funny, because his biological parents were huge drug addicts and now he is one too, which is nature/nurture nastiness that is so characteristic of this show. Like, of course he's a drug addict, and that's why you should never adopt a child because eventually their crackhead genes will come out.
In her disgusting sad apartment, Susan presents Dave Foley with a crystal mouse holding a crystal heart. It's about the tackiest thing you've ever seen, and of course she's like, "I looked for a crystal kidney, like the one that's being ripped out of your body!" It's grim and yucky and ever so Susan. In return, Dave Foley presents her with a scrapbook of his lifetime of stalking her, which includes photos both yearbook and surveillance, and a lock of her hair, and finally the secondary brain in her tail gets the message to her main brain that she is in a desperately Susan situation. But instead of telling him this is a terrible idea, she just lets him scoot closer and closer on the couch and refuses to tell him about her giant sexy husband or their awful son, because it's rare that Susan gets to be a martyr and use people's feelings against them at the same time, so this is like Susan heaven.