Awhile ago, when the girls were hanging out in Emily's bedroom, Alison got worked up because she claimed Jenna's brother was spying on them. She therefore convinced them to get revenge by setting off a stink bomb where he lives. But when it went off, this bomb created more of an explosion than some normal novelty item and we're led to believe Jenna was in the room when it did its damage.
Jenna's return to school isn't all the gals have to worry about: the detective that Hanna's mom slept with (and who continues to be a presence in that family's life) grills the friends and says he knows they had something to do with Alison's death. They all deny it, of course, but admit to each other that they're lying about drinking that night at least. Spencer also tells the group Alison had a boyfriend at the time, but the cop doesn't get this information.
Additionally, we learn the following about each girl:
- Mr. Fitz can't hide his feelings for Aria. He shows up at the movies with her and her mom and gives her a ride home in the rain one time. They end up making out hardcore in his car.
- Emily and Mona grow a lot closer, as Emily seems more distraught than most about A's death and is seemingly confused about her sexuality. We also meet her boyfriend, Ben.
- Hanna has a boyfriend named Sean, whose dad is a pastor. They haven't slept together because he wants to wait.
- Spencer makes out with Wren, her sister's fiance. Melissa sees this happen and then we later see Wren moving his stuff out.
- At the end of the episode, Spencer sees Jenna sitting on a bench and telling her phone to send a text. Has she been the one sending texts from A to the girls? They've each received them throughout the hour, making it clear someone knows all their actions/secrets.
Source: TV Fanatic