Wendy and Noser go to the police station to get Lacey out of jail after she was arrested for indecent exposure in a sushi restaurant. The desk sergeant finally lets Lacey go but Wendy is too exhausted to give her a hug back. When she says Lacey's pranks are pointless, Lacey blows up at her.
The next morning at Middleman HQ, Wendy comes in looking for coffee and explains what happens, and how she ended up sounding like her mother. The Middleman figures they'll make up but Wendy suggests they use the computers to wipe out Lacey's permanent record. They get a new case but The Middleman suggests she sit it out. Wendy refuses and they go to check out the new case: a mudslide in a Chinese restaurant. They arrive to find the owner smothered to death in a pile of mud. The Middleman has Wendy look the scene over and she notices a terracotta warrior statue is missing and identifies it from a sheet. They talk to the busboy who saw the owner Mr. Su buried by mud, and was obsessed with the statue, chanting to it in Mandarin.
On the way back to HQ, The Middleman admits he doesn't have a clue as he's not familiar with magic. He takes them to a consultant: Roxy Wasserman, who runs a fashion house. The Middleman explains that Roxy is a reformed succubus who runs a halfway house for soul-sucking demons. Roxy identifies the statue as an earth elemental, which can manipulate anything, and goes to work on a potion as water beats earth. However, she warns that the terracotta warriors were on a mission to find the last heir to the Emperor, take that person to the underworld, and unleash a hail of fire lasting a thousand years.
The Middleman gives Wendy an inoculation en route as they prepare to go to China, and then drops her off at her sublet. She discovers Lacey talking to her mother and then mentions that she's "working" for Roxy. Lacey knows Roxy as someone who uses furs and prepares to go to the fashion house and throw some fake blood. When Wendy starts to object, Lacey angrily says she won't be calling her. Wendy then goes to Roxy's fashion house and mentions fur coats, but Roxy doesn't plan on using fur coats for her summer shoot. She then tests Lacey on her ability to accessorize and is duly impressed, and hires her as her new assistant.
At Middleman HQ, Wendy tries to call Lacey while Ida tries to locate the heir. The Middleman gives Wendy a few seconds to talk it out but assures her that the succubi are completely reformed. Ida comes up with a match: the heir is Duncan. They go to the junior high to track down Duncan. Meanwhile Lacey is dealing with her new duties, which include assembling the components for the water potion. When she hears that she has to get Tahiti Water, which is environmentally unsafe, she objects but Roxy doesn't care. She chats with a sympathetic Trevor, who seems interested in her... or at least her soul.
The partners find Duncan on the playground but are interrupted when the Warrior appears from the bricks on the roof. The Middleman temporarily blasts the Warrior apart and they escape while it reassembles itself. They get a call that Roxy has finished the potion and go to Duncan's home, where Lacey delivers the potion for her boss. The Middleman takes it and the two flirt back and forth while Wendy wonders what Lacey is up to. After she leaves, they go inside and talk to Duncan's parents. His mother Jessica finally admits that she had an affair while she was in Shanghai. The two of them go out of the room, leaving Duncan, and Wendy tries to reassure him saying that her father disappeared when he was 14. They're interrupted when the Warrior enters the house and demands the heir. The Middleman throws the potion… and it has no effect. Wendy realizes that Lacey must have substituted tap water. The Warrior buries the partners in mud and takes the boy.
The Middleman and Wendy head back to Roxy's, and Wendy blames herself for driving Lacey into the job. The Middleman says they need to talk later and promises to explain later. Roxy is working on another potion and blames Lacey, and Wendy takes offense. She finally determines that Roxy dealt with Lacy… non-violently. She then calculates the Warrior's route and shows that there is a new route that The Middleman can take. Roxy advises him to go alone but The Middleman has faith in Wendy. Roxy orders her minions to open a portal to the Underworld. Outside, Trevor talks to Lacey who admits she needs Wendy. However, when Trevor offers to help Lacey thinks of one thing he can do.
Dressed in Grecian robes, the partners prepare to go to the Underworld. The Middleman is armed with a scythe that he has to hold to protect them from the dangers of the Underworld. He tries to make Wendy feel better by telling her a story about he got one of his teammates badly injured when he was pining over a girl. He insists he'll give Wendy a hundred percent and expects her to do the same.
Roxy begins the ritual and the partners find themselves in… an office building lobby. They go to the information desk and Wendy notices a file room which The Middleman explains is a repository for the records of everyone who has ever died. They finally get the attention of the clerk who directs them upstairs. However, Wendy stays behind to get information on her father. When he refuses, she draws a gun on him but he's already dead. He concedes that she's funny and decides to help her.
The Middleman finds the Warriors and attacks him, then orders Wendy to throw the potion only to realize she's not there. He grabs Duncan and runs downstairs just as the clerk delivers her father's file. She runs upstairs, they meet, and head back downstairs to the elevator/portal. They get in and she throws the potion, destroying the Warrior in a large muddy explosion. They return to Roxy's fashion house… covered in mud but otherwise unharmed.
The Middleman drops Wendy off at her apartment and she admits she let her personal life interfere. He says she came through in the end and that's all that matters, and she thinks her dad would have been proud. The Middleman notes that maybe he still is.
As she goes up to her sublet she sees Lacey and Trevor coming down. She apologizes to Lacey, who explains that she took the job so she could get to Roxy's fur room. But then she thought about what Wendy said and came up with a new plan: she asked Roxy to donate the furs and now she's giving them to homeless people.