Teens stumbled upon a murder scene and posted the location on Facebook where, of course, Milt has a lot of Likes.
There is a foot with a knock-off foot sans the rest of the body. Russ doesn't need a whole lot more to go off of to know there is criminal activity involved given that shoe because he got them every birthday growing up.
Russ' mother is in prison and used to give them to him. It calls for a visit. She's wary of Milt right off the bat. Good looking people don't get demoted, so she wonders what's up. She immediately begins conning Milt and Russ calls him a fool, saying he does foolish things. One of the foolish things is when Milt decides to get her out of prison so she can help them find the killer.
Milt realizes that Russ and his mother make an extraordinary team. They go to eat Chinese and Russ can't because there's a killer on the loose. Constance reminds him there is always a killer on the loose, so you might as well as eat. Then she walks to the kitchen so she can buy a knock off Prada bag.
Constance needs new clothes to do this well, so they take her clothes shopping where all of the women in the store hit on Milt. Russ finds it annoying, especially that Milt doesn't notice. Milt tells him he notices where Russ got his deductive reasoning skills. Constance raises Russ' credit limit when he doesn't have enough because he used his mother's maiden name as his security question.
A man shows up at the precinct asking Holly questions about Russ and his civilian complaints and talks her into giving bad press about him.
Constance goes into a house to talk with a man without a wire and when she screams, Russ and Milt break in only to find her having sex with the man in the house. She hijacked the investigation to get laid.
After all of that, it's discovered the murder victim is Constance's old partner. She just wants to go back to prison where she's safe.
Their con was to slip burner phones into iPhone stores so Constance could come in with fake burns and get the store to settle. Constance's partner was a young kid. When Russ and Milt visit his father, he tells them his portion of the settlement was $1 million. Constance said the full settlement was $1 million. Where's the rest of the settlement?
The Commissioner tells Holly not to worry about Russ. He'll be fine.
While Constance is telling Font people are idiots, Milt and Russ walk in. Oh mother...
The murder weapon is found. It's connected to Joe Ryan. Jo Ryan is one of Russ' mother's aliases. Russ' mother is their killer. Constance is insulted Russ would think he would kill someone and then dump the weapon with the body.
Even when Russ says he's spent his whole life worrying she was going to get hurt and begs her to tell him where the money is, she still says there is no money.
Russ and Milt go in search of the missing money in Constance's storage garage. Instead of finding money, they find a whole lot of normal -- pieces of Russ' childhood including photos of him acting a trophies.
Holly lays in wait for the reporter to return. She found a lot of convictions on his record for DUIs and such. He says this proves how corrupt the precinct really is and he'll will a Pulitzer. She says she learned working there that convictions are nothing in comparison to what doesn't show on his record and she'll find it. He promises to drop the story.
During a lie detector test, Milt asks Constance if she loves her son and when she says yes, the answer proves false. He's gutted.
After she's driven off in a police van, a police van comes around and a cop says he's her to pick up Constance Agnew. Constance is with her man. She asks him if she knows he always loved her, right? He says yes and then knees him in the balls.
Russ and Milt are in a car, following a signal. Russ conned everyone. However, Fon'ts phone died. Now Russ has to figure out where Constance was going. Milt realizes if the polygraph was wrong, it was also wrong about Russ' mother loving him. Russ knows where she is.
Henry is holding a gun on Constance in the storage garage. Constance cannot believe she was conned.
A reporter comes in and Holly asks her about Max Archer. Constance smiles from across the room when Holly learns the guy doesn't match the description. She had to know Holly was good enough for her son.
Milt calls his mother, who doesn't want to talk to him.
Russ takes his mom to the prison van, gives her a truly heartfelt hug goodbye.