DCs Rob Thatcher and Brandon Kane raid the house of a heroin dealer after several addicts have died from a bad batch. Thatcher is determined to catch the supplier, and once again, he goes too far and arrests a suspect: Alan Best - PC Gary Best's father, who is working as a police informant for Insp. Gina Gold. Sgt. Sheelagh Murphy tells PC Des Taviner she is going to leave her husband for him - but Taviner has other matters on his mind. PC Reg Hollis warns his friend that PI Sally Johnson is closer to the truth about the Sun Hill fire than ever, and at a memorial ceremony for the officers who died that day, Taviner is too overcome with guilt to make a speech. Determined to be honest with Murphy, Taviner admits he framed Jeff Simpson for the fire, but Johnson tells DCI Jack Meadows that Taviner's involvement may go further than that.