Happy Bones Day Everyone !
The Couple in the Cave airs tonight at 8/7 C on Fox
Here is the official description of the episode:
A couple's remains that are discovered in a National Park cave create a double mystery: who are they and why were they killed? Elsewhere; Booth's girlfriend drops by, unexpectedly stateside from her assignment as a correspondent in Afghanistan, which leaves Brennan unsure of her relationship with Booth.