Ashes to Ashes (2008)

S3E4 Episode 4

Gene discovers that an undercover operation to catch several drug dealers is taking place on his patch without his knowledge. Determined to take control Hunt blows the cover of an undercover operative who turns up at CID and is eventually placed under his protection, yet it seems someone on the inside is twisting things to help the drug dealers stay out on the streets. Meanwhile, the deceased police officer continues to haunt Alex. Could he actually be her key to getting home?