Things get weird when the girls come across a creepy mask maker on Pretty Little Liars. "Cat's Cradle" is the third episode of the show's fourth season.
Added:

Pretty Little Liars Season 4 Episode 3 Quotes

Melissa: Do you suppose other sisters have as much trouble getting along as we do?
Spencer: Uh, there might be a few.
Melissa: Maybe we're just too much alike, and that's the problem.

What? We can't make a move without Nancy Drew?

Hannah