Motive: 6 Months Later

SINOPSE

The killer: Derek Caster. The victim: London Montgomery, the grown daughter of wealthy industrialist, Neville Montgomery. Six months out of drug rehab and seemingly clean during that time, London is found dead from being poisoned on what was the night of her birthday party joint drug rehab facility fundraiser. Betty suspects that the drug was purposefully given to London as what she believed was cocaine. Oscar recuses himself from the case when he learns that the last person to text London before she died was his father, Franco Vega, who has a thing for younger women like London. As such, Franco becomes a prime suspect. Because of the need for extra human resources on the case, Boyd asks Angie if she is willing to be temporarily placed back in Homicide from her desk job in Recruiting which she requested six months ago following Oscar killing to protect her, and her and Mark's ten year secret coming to a head. The desk job has not rejuvenated Angie as she had hoped, and as such she is itching to get back to Homicide permanently. The detectives learn that London was working through a twelve step program, and was on step nine - making amends - with one person who did not accept her apology probably the killer. Working through the evidence and learning the nature of Franco and London's relationship, they learn that London's death is indirectly related to Neville's business dealings, which they suspect will play a major role in their future work based on the outcome of this case.