Episode 26 of "Bones"
s02e04 The Blonde in the Game

Moments after Booth and Brennan unearth the skeletal remains of a young girl, it becomes clear they aren't dealing with just any murder case. Hodgins, Zack and Cam confirm this back at the lab when they discover that the cause of death points straight to Howard Epps, a convicted serial killer who has been on death row for years... Brennan's previous testimony in his case gave Epps a stay of execution. Booth interrogates Epps, seemingly to no avail, but after finding a clue on the deceased girl that leads them to another young body - this one only a week old - they realize that Epps is forcing them to play a deadly game. As the body count rises, Brennan and her team scramble to decipher Epps' cryptic clues in a desperate effort to find his cold-blooded accomplice. The team is pushed even further when it is revealed that the latest victim may still be alive, with only hours left to live. As precious seconds tick away, Brennan and her team must test their limits and confront their fears to save a young girl from becoming a victim.