I'm just gonna say, even for this show, this is one hell of an episode. Absolutely brilliant from start to finish.
Spencer got chased through a church like a million years ago, which resulted in Ian dying like six or seven times, and also involved her throwing the USB drive into the pews to distract him. As with most pieces of evidence, especially when Spencer's involved, nobody remembered it after the fact. Cece Drake showed up out of nowhere, and proceeded to act like a boss. Ezra's 99 problems included a babymama. Noel Kahn's cabin has a secret robot murder room, which attacked Hanna's leg. Paige is on a rampage because of Emily accidentally kissing Cousin Nate.
Hanna: "How come I'm the only one who has to actually heal at a normal rate? Now, Spencer, I've asked you here because I simply need the most hideous clothing to distract from my sucking leg wound, and Aria is busy."
Spencer: "That giant peasant skirt should do it. You look like the Gyptians."
Hanna: "Perfect! Now nobody will notice my tiny leg bandage."
Spencer: "And yet nothing about your plainly visible bra."
Wren calls and Hanna acts super incredibly shady about it, setting off Spencer's understanding of the obvious, and even refers to him as "Downton Grabby," which is amazing, but Hanna blows it off.
Pastor Ted: "Hey, I found this thumb drive in my church from that time Ian tried to kill Spencer. It's got weird footage of your daughter being spied on."
(Hanna & Spencer: "Eventually our habit of completely forgetting evidence after every episode was going to bite us in the ass, I suppose.")
Ashley: "Well, there was some shit that once went down. Perhaps you've heard of the ongoing tragedy and near-constant murder that is my daughter's regular life?"
(Hanna: "Okay, here's the thing about that thumb drive though, is that it has Jenna's rape footage on it. If he takes it to the cops, she'll think that we sold her out! And I would never do that, because I'm such a good friend.")
Ashley randomly ends up with the USB drive and puts it down for a sec, but then surprises the girls trying to snatch it.
Ashley: "What the fuck? Is this Mona stuff?"
Hanna: "Yeah, it's no big deal. Just don't give it to the cops, they'll move her away."
Ashley: "Guess what, I am not hugely in favor of Mona. I'm going to arbitrarily watch these in the future. Now get your shit and get in the car. We need to talk about your horrible outfit."