June and Cass are called to the flat of a prostitute named Allie after tracing malicious calls made from her phone, only to find her lying unconscious on the floor from a vicious assault. Turning her over reveals the words 'Join The Club' written on her back. The case matches several other recent assaults on prostitutes in the area, most of whom are being pimped by Robert Stern. After being apprehended it is revealed that Stern attacked Allie but was not responsible for the calls she made or the writing on her back. Meanwhile June saves Beth, another of the victims, from throwing herself under a train believing herself to be HIV positive after her attacker revealed this to be the words sinister meaning. When he is eventually caught and brought back to the station, Liz identifies him as ex-boyfriend Andy Marshall, a search of his houseboat turns up HIV medication. The calls were being made to his wife Julia Marshall who is pregnant and living on her own, unaware of his supposed HIV stat