Three men are found dead in one night, all victims of fatal gun shot wounds. One is killed in bar, one is found dead in the street, apparently dumped from a car, and the third is found in an apartment that belongs to the man in the bar. The three victims are identified as Michael Jones, Duckins LaBranch and Luther Stockton--three drug dealers who were set to go to trial for murder the next day. The ADA on the case, Natalie Greer, tells Mac the men were going to rat out another dealer in exchange for lessened sentences, and sends him to Jones's lawyer, Jacob Donovan. Donovan tells Mac that the men were going to rat out a dealer named Petrix DeRosier. Before going with Flack to question Petrix, Danny discovers the two recovered murder weapons were the ones the three men used when they killed their victim. Danny and Flack question Petrix, but he gives them nothing, simply noting that the murders were bad for his business. Stella and Detective Angell find the vehicle Duckins was killed in--it was stolen by the prostitute he was with when he was killed. She denies killing him, but Angell notices blood on her bra, and Stella finds the third murder weapon in the car. As the case proceeds, Mac finds himself facing a very different problem: Adam and six other lab techs are being let go in a month due to budget cuts. Mac fights Sinclair for Adam's job and posits waiting six months to purchase state-of-the-art automated work stations, but Stella reminds him how crucial the workstations are, and says they'll have to find another way to save Adam's job.
Stella investigates stun gun marks on Duckins' body and traces them to Maggie Hall--a woman who was attacked, her face brutally cut, a week ago by the three murder victims. Maggie was set to testify in the trial against the three, something which shocks Mac, since he promised her based on the strength of the evidence that she wouldn't have to testify. Maggie's three brothers are enraged, and Mac returns to ADA Greer, who tells him some of the evidence was compromised, forcing them to call on Maggie. Petrix DeRosier is cleared based on electronic surveillance evidence which places him nowhere near the scene of any of the crimes, and Lindsay posits that a substance found on one of the guns could link it to Maggie's brother Kevin, who works at a grocery store. Three brothers, three murders--but none of them are talking. Adam finally manages to get a print off some glass from the bar Danny has left him to reassemble; it's a match for Jacob Donovan, Michael Jones' lawyer. Mac brings in the three men's lawyers and he, Danny and Flack question them. Disgusted after the attack on Maggie, Donovan concocted the plan to do away with their disreputable clients. All three lawyers killed each of their clients at the same time. Donovan won't give Mac an official confession; he's convinced he can get a young, eager attorney to work the system and get them acquitted. The case solved, the team members come into Mac's office one by one and give up their paid vacations in order to buy Adam more time on the job until Mac can come up with a more permanent solution.