Without a Trace · S4, E10
When Darkness Falls
Samantha investigates the case of a woman with amnesia who may not only be a missing person but a murderer. Meanwhile, Jack's father, Frank, who is battling Alzheimer's disease, no longer has the will to live as his condition grows increasingly worse, and Jack feels that he has no choice but to have his father declared incompetent so he can get the treatment he needs.
