BONES: Exclusive Scoop on “The Monster in the Closet”

It's the serial killer arc we've all been waiting for ever since Bones EP Michael Peterson uttered the words "Big Bad" on a recent conference call.

“The Monster in the Closet” will see the Jeffersonian investigating the decomposing body of a social worker in the park. So far so regular episode of Bones, right?

However the investigation takes a big jump to the left when the collected evidence suggests the killer lived with the body for months before dumping it.

Things get even more complicated when they realize another set of cold case remains in Limbo share details which link both victims to a serial murderer who had sinister interactions with his victims’ bodies.

The episode welcomes back behavioral analyst Karen Delfs (guest star Sara Rue) who cuts through the seriousness of this week's installment by bringing some much needed levity to proceedings.

Meanwhile, Pej Vahdat's Arastoo also returns, prompting Cam to make a decision about what and who she wants most in her life.

We've seen the episode a little early, thanks to our friends at FOX, and have a number of teasers to share with you. As usual, we have chosen to avoid outright revelations and plot points that could take away from your experience of the episode. However, we urge you to exercise your regular degree of caution around spoilers, because this is the internet and who are these ScreenSpy people anyway?