After reminiscing fondly about his old partner's dog, Detective Dan Stark and his new partner, Detective Jack Bailey, watch as the house they just walked away from explodes.
Bailey and Stark have been working a case involving a string of dog poisonings, which Stark believes will bring them "face-to-face with a sociopath."
Meanwhile, we see a true sociopath at work: Chinese hit man Mr. Chen is buying some guns from a guy who keeps them in his refrigerator. Chen then kills a man who argues about a bad shipment of crystal meth ingredients. Lee Huang, Chen's interpreter, watches in horror while Chen commits the cold-blooded murder.
As Stark and Bailey continue looking for the person responsible for the dog poisonings, Stark spots a possible suspect in an El Camino. Bailey traces the license plate number to a house, which the detectives get to in time to narrowly avoid being blown up. Unbeknownst the detectives, the driver of the El Camino was watching them the whole time.
Lieutenant Ruiz sarcastically says she's amazed at the banner day for the department: "$100,000 in damages for a dog and a police report written by Dan Stark," an item so rare, Ruiz says she might just frame it. The lieutenant rightly doesn't believe Stark's report, but with Bailey's confirmation of the story, she reluctantly gives the boys the OK to investigate the case further.
As Stark and Bailey argue over the validity of the events in Dan's report -- all of which did happen, "just not in that order" -- Liz offers Bailey a pair of Ryan Adams concert tickets, since her date, Kyle, double-booked a client. Stark thinks Bailey's bittersweet feelings about Liz mean that he's in need of some Foghat and some busting of punks. Chen's interpreter, Huang, is sitting in a car and on the phone with a cousin, explaining how scared he is of the ruthless hit man. Then Chen gets in and holds up an address: 1512 Palm Avenue. That's where Terrence Spivey lives -- and also where our heroes are at that moment.
Stark shows Spivey a picture of the suspected doggie slayer. Claiming he's never seen him before, Spivey watches as the cops leave. He then walks to the back of his house, which doubles as a meth lab of his own, bringing us to the beginning of the episode. We see the detectives almost get blown up again as Chen and Huang are driving by.
The rest of Dallas P.D. comes to help with the investigation, and the boys argue that a man named Steve Maxson is trying to take over the South Dallas drug trade. After praising their "uncharacteristically good work," Ruiz wants the guys to debrief with Narcotics; Stark and Bailey vehemently protest. They persuade Ruiz that they've earned the right to keep going on with their investigation. Meanwhile, Chen continues trying to find out who has been tampering with his client's drug materials. As Huang interprets, he explains to Chen's victim his own unfortunate situation, urging him to call 911 after they've left.
In another part of town, Stark and Bailey interview a possible witness, and Dan can't resist hitting on her, as he describes the ins and outs of riding a mechanical bull. After Stark shares with Bailey some of his techniques for making the ladies swoon, the pair's next stop brings them to the local chemical store, where the counter girl tells them that Maxson frequents the place and asked about nearby hotels yesterday.
Stark and Bailey close in, but instead of a shootout, they find Maxson crying over his daughter, Emily, who is a meth addict. Maxson says he only wanted to render the meth inert so that the bakers couldn't make the drug, but according to Bailey, "the tweakers just kept adding red phosphorous until...kaboom."
Ruiz is annoyed that the supposedly dangerous man they've been looking for is just a concerned father, but she reluctantly allows the guys to stay on the case. They give Maxson a deal that will have him serve 18 months in jail, much to the dismay of Stark, who believes that the unassuming Maxson will get eaten alive in prison.
Meanwhile, Spivey, while questioning Joey about the shipment, figures out that it's actually Joey's driver, Maxson, who's been tampering with the chemicals.
Bailey is excited about the prospect of getting bigger cases if they successfully close this one, but Stark reminds him that the most important thing is to keep Maxson alive and "bust some bad guys. Maxson botches his undercover work, but before Spivey and his goons can kill him, Chen enters. He takes out one of Spivey's men, and then everyone heads for cover and starts shooting. During the ensuing fracas, Stark and Bailey find an explosive way into the lab. Chen demands that his interpreter start shooting, but Huang protests and nervously drops his gun, which goes off, killing the assassin.
Joey holds the cops at gunpoint, but Maxson kills him, saving their lives. Before their backup arrives, Bailey has a change of heart and gives Maxson money to leave town. Unfortunately, the good deed leaves Ruiz flummoxed as to how Maxson, a man who cried so hard that he puked into a garbage can, could overpower two trained officers. And Bailey realizes that they won't be seeing bigger cases anytime soon.