"Toxic Relationships" is the 25th episode of the 29th series of Casualty. It was preceded by "Excess Baggage" and followed by "The Road Not Taken". The episode takes place on the same day as the previous episode.
Lily is involved in an accident on the way home from work, which sees her moped collide with a schoolgirl. The accident could jeopardise her career, but was it her fault?
Meanwhile, a couple risk losing their baby when traces of amphetamines are found in mother and baby's urine samples. Their neighbour Mike is also brought into the emergency department with burns following an explosion in his meth lab.
Elsewhere, the team is overworked and Connie and Rita continue to argue. Rita starts a work to rule, telling the nursing staff to only do tasks which are specifically in their job description and decline any other requests.
Also this week, Cal steals money from Ethan for Taylor's charity.