Pretty Little Liars: The Perfectionists' Janel Parrish, Sydney Park On 'Dark Side' Of Spin-Off

"Pretty Little Liars: The Perfectionists" stars Janel Parrish and Sydney Park, who play Mona and Caitlin, dish on the "dark side" of the new PLL spin-off and what's about to go down in the town of Beacon Heights.