Caleb and Toby team up to investigate "A" and what really happened the night of the lodge fire.
Toby and Spencer visit Ravenswood -- which is unlike any place they've ever seen.
Spencer and Emily make plans to visit a nearby college, but they have very different agendas.
Toby finds a new source of information into his mother's death, but it only leads to more questions.
A clue in Ali's things leads the Liars to a creepy mask maker.
The presence of Mrs. DiLaurentis in Rosewood continues to unnerve all those around her.
In the season four premiere, the girls turn to Mona for answers.
A special episode encompassing the first three seasons of Pretty Little Liars.