ABC Family is making the first act of the highly-anticipated 100th episode of their hit original series “Pretty Little Liars” available to viewers for the next 15 hours via its authenticated WATCH ABC Family service until midnight tonight.

WATCH ABC Family allows viewers with participating TV subscription services access to 24/7 live viewing of the network, as well as on-demand access to the most-current episodes of the network’s popular series at home and on-the-go via a wide array of devices, including desktops, smartphones and tablets

In “Miss Me x 100,” the 100th episode of “Pretty Little Liars,” the day has finally arrived – Alison’s first day back at Rosewood High, and neither the PLLs nor Alison are really ready for it. Determined to put on a brave face, Alison returns to also help heal the damage she did years ago. But are apologies enough for those who Alison has hurt in the past? Not if Mona and her army have anything to say about it.

Meanwhile, Caleb and an old foe return to Rosewood.