A girl can't remember killing her best friend, despite holding the murder weapon, so Jane finds a way to jog her memory.
A patient with Alzheimer's disease brings back difficult memories for Richard and April, while Jackson struggles to return to normal life.
Jane and Maura literally race to find a killer at the Boston Marathon who shoots runners during the event.
Denise represents a plastic surgeon who is being sued for his unconventional working methods, while Shirley is emotionally touched when dealing with a client with Alzheimer's.
A young girl is found murdered, and when Megan arrives at the scene, she finds Tommy covered in blood. As the evidence piles up against him, Tommy claims he cannot remember what happened the previous night.