Having caught Rachel in bed with their colleague Kevin, Janet throws her out of of her house. Frosty relations notwithstanding, they investigate the death of 61 year-old Kenneth Valentine who is found in a back alley. He had an argument with his son Philip earlier that evening over their current living arrangements and while Janet and Rachel find Philip to be a bit odd, he does seem to have an alibi. The investigation gets on the right track when the robbery squad reports a series robberies at knife point that same evening. Meanwhile, Rachel ends her relationship once and for all with Sean. Everyone on the team is devastated when the identity of the mole is revealed.
—garykmcd