Doherty, riding on his motorcycle, is first to arrive at a multivehicle collision; Taylor is hit by a car; Tatiana goes to see Chevchenko, and tragedy ensues.

Bosco is dismayed as he watches Cruz go to the extreme lengths of planting drugs, frightening children, and faking a dying declaration in their attempt to arrest the drug dealer who killed another dealer and then tried to to kill the 12 year old boy who witnessed the crime; Nancy tells Ty that she's ending her relationship with Hancock, and gives Ty the ammunition he needs to get out from under Hancock's thumb and back to duty at the 55, as well as getting Sully's suspension from duty lifted.

Sully is sober and back on the job; Faith continues to keep a close watch on Emily; a mutual attraction springs up between Kim and a reporter; Faith and Bosco pursue a man after he steals a bag of money from an overturned armored car involved in a fatal accident; Faith is unable to dissuade Bosco from wanting to hide the cash after the robber drops it, rather than carrying such a heavy load during a foot chase, and is proved right when they return later to retrieve the bag and find that it's been stolen yet again; faced with disciplinary action and investigations by the Major Case Squad and IAB, they pound the pavement trying to find the second perp and discover that the accident with the armored car had been staged by one of the guards and his girlfriend; Maritza ends up stealing the first perp's collar from Faith, which further erodes their relationship; Bosco is jealous when the Major Case Squad detective running the investigation turns out to be Maritza's former boyfriend; as Doc and Kim rush Nicole West to Mercy after a suicide attempt, she tells Kim that her stepfather Anthony has been molesting her; when Nicole's mother refuses to believe that her husband has done anything wrong, Kim implores Melinda to see that her daughter is crying out for help with repeated suicide attempts; after Nicole convinces Melinda that Anthony is guilty and reveals that her accusations against Carlos were false, Melinda apologizes and withdraws her complaint against Carlos and the city; still at odds over trust and honesty issues, Faith and Bosco trade painfully honest barbs and decide to split up; Carlos is elated when Ty tells him he's being reinstated.

Yokas clashes with her mother over her recovery; Maritza is back on the job, but unhappy that she's back in the bag and handing out parking tickets; Ty and Sully discover a truck carrying sick illegal aliens and end up scouring the city to track down one of them who escapes after it's determined that the aliens have a highly contagious and potentially fatal disease.

Doc is demoted back to the streets and continues his downward spiral, presenting Kim with no end of problems as he lies about his demotion, resists her orders as the supervising paramedic, and deliberately runs down a perp with the bus; Barnes is shanked at Riker's for doing a flip on Buford; Carlos is devastated when Kylie is diagnosed with aplastic anemia and he's not a match for a bone marrow donation; Sully tries to deflect Ty's teasing about his relationship with Barbara by getting him to focus on their LSAT prep; after a horrific gunfight, Maritza finally captures Lettie's killer and decides to spare him so that he can suffer for the rest of his life in prison.