Contains spoilers for this episode and earlier episodes.
A prosecutor asks the Lightman Group to identify which teenager drove a stolen vehicle in the collision that killed baseball player Juan Salazar. A paramedic, Ilene Clarke, helped the survivors, and the prosecution wants a murder charge. Torres questions Mark Jackson, who accepts responsibility for the crash but insists his light was green. Lightman also has a collision after questioning Ilene, forcing the team to consider whether the traffic signals were manipulated.
Ilene's repeated appearances at crashes initially suggest that she creates emergencies so she can act as a rescuer. Investigating her childhood instead reveals her brother Kent's control over her. Their mother died in a crash after being distracted by Ilene, leaving Kent injured and bitter. He has copied the signal used by emergency vehicles to change lights, causing crashes and forcing his sister to save the victims as punishment for failing to save their mother.
Kent deliberately places himself in another collision and refuses treatment, trying to make Ilene watch him die. With Cal's intervention, she treats his collapsed lung and stabilises him. He survives, and Ilene later accepts the consequences of her part in concealing the crimes while describing relief at being free of his control. The prosecutor reduces Mark's charges, although he still faces prison for stealing the vehicle. Cal returns home to recover, where Emily tests his memory and teases him over old family photographs.