A woman who is found dead with her tongue cut-out turns out to be an NYPD officer turned DEA undercover infiltrating the Columbian drug cartel. DEA learns that Benson and Stabler are investigating the murder and quickly move-in and play big brother. They allow SVU to investigate, but only as far as the murder. The detectives step on toes, however, when one of the DEA informants comes forward and leads them to cartel boss' boat where he killed the woman.