-A firefighter dies in a factory fire. Maura investigates the cause of death.
-Maura's mother, Constance visits. When a car tries to run Maura down, Constance pushes her out of the way and is hit herself. She requires emergency surgery and is in critical condition.
-Patty Doyle turns up and tries to protect Maura and her mother. He offers to tell Maura who her biological mother is but she says Constance is her real mother. Patty promises to tell her someday when she isn't so upset.
-Agent Gabriel Dean returns and rekindles his romance with Jane. She is torn because of her relationship with Casey but ends up sleeping with Gabriel.
-Jane tells Gabriel that Patty Doyle has surfaced but asks him not to do anything about it just yet. He agrees.
-Turns out Maura was almost run down because she came too close to uncovering a string of arsons. She sets up the firefighter who caused the blazes and gets him to follow her to the warehouse.
-When the firefighter tries to kill Maura, Jane and Frost are there but Patty Doyle shoots the man first. Agent Dean shows up following Doyle and a firefight ensues. Jane shoots Doyle. When Jane goes near Doyle, Maura becomes angry and won't let her near her father.