DC Stevie Moss watches helplessly as junkie Danny Peters injects a heroin-filled syringe into DS Stuart Turner's neck. When Danny backs off, Stevie rushes to Stuart's aid, and Pcs Tony Stamp and Roger Valentine also help Stuart, whose condition is deteriorating. As Danny is arrested, he boasts that the needle was infected with HIV. While Stuart waits to learn if he has contracted the virus, he turns up at Sun Hill determined to keep busy. But he's frustrated to learn that Danny has agreed to disclose information on a major heroin smuggling operation - providing the police put in a good word for him when he gets to court. To find out more about the drugs deal, Stevie goes undercover as a heroin-addicted prostitute, and meets Paula, who used to be one of Danny's girls and now works for the heroin dealers. But the sting goes badly wrong when the women are locked in the back of a van - and Stevie has no way of contacting her colleagues at Sun Hill...
